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[http://www.karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_History The Story of Mathematics]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_History The Story of Mathematics]
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|[http://www.karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Philosophy Philosophy of Mathematics]
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|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|[http://karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Philosophy Philosophy of Mathematics]
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
[http://www.karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Pedagogy Teaching of Mathematics]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Pedagogy Teaching of Mathematics]
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
[http://www.karnatakaeducation.org.in/KOER/en/index.php/Maths:_Curriculum_and_Syllabus Curriculum and Syllabus]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Maths:_Curriculum_and_Syllabus Curriculum and Syllabus]
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
[http://www.karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Topics Topics in School Mathematics]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Mathematics:_Topics Topics in School Mathematics]
 
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|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
[http://www.karnatakaeducation.org.in/KOER/en/index.php/Text_Books#Mathematics_-_Textbooks Textbooks]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Text_Books#Mathematics_-_Textbooks Textbooks]
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
 
|style=" width:10%; border:none; border-radius:5px;box-shadow: 10px 10px 10px #888888; background:#f9f9ff; vertical-align:middle; text-align:center; "|
[http://www.karnatakaeducation.org.in/KOER/en/index.php/Maths:_Question_Papers Question Bank]
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[http://karnatakaeducation.org.in/KOER/en/index.php/Maths:_Question_Papers Question Bank]
 
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While creating a resource page, please click here for a resource creation [http://karnatakaeducation.org.in/KOER/en/index.php/Resource_Creation_Checklist '''checklist'''].
 
While creating a resource page, please click here for a resource creation [http://karnatakaeducation.org.in/KOER/en/index.php/Resource_Creation_Checklist '''checklist'''].
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= Concept Map =
 
= Concept Map =
 
__FORCETOC__
 
__FORCETOC__
<mm>[[Circles_Constructions.mm|flash]]</mm>
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[[File:Circles_Constructions.mm|flash]]
    
= Textbook =
 
= Textbook =
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|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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{| style="height:10px; float:right; align:center;"
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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*Question Corner
 
*Question Corner
   −
==Concept #3. Construction of direct common tangent.==
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===Learning objectives===
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===Notes for teachers===
   
===Activity No # ===
 
===Activity No # ===
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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*Evaluation
 
*Evaluation
 
*Question Corner
 
*Question Corner
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==Concept #3. Construction of direct common tangent.==
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===Learning objectives===
 +
===Notes for teachers===
 
===Activity No # ===
 
===Activity No # ===
 
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{| style="height:10px; float:right; align:center;"
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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*Evaluation
 
*Evaluation
 
*Question Corner
 
*Question Corner
  −
==Concept #3. Construction of direct common tangent.==
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===Learning objectives===
  −
===Notes for teachers===
   
===Activity No # ===
 
===Activity No # ===
 
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{| style="height:10px; float:right; align:center;"
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
*Estimated Time
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*Evaluation
 
*Evaluation
 
*Question Corner
 
*Question Corner
===Activity No # ===
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===Activity No # Construct a direct common tangent to two circles with given radii and given distance between the centre of two circles.===
 
{| style="height:10px; float:right; align:center;"
 
{| style="height:10px; float:right; align:center;"
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
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*Estimated Time: 90 minutes
*Materials/ Resources needed
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*Materials/ Resources needed: # Laptop, geogebra file, projector and a pointer.
*Prerequisites/Instructions, if any
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# Students' individual construction materials.
*Multimedia resources
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*Prerequisites/Instructions, if any:
 +
# The students should have prior knowledge of a circle , tangent and the limiting case of a
 +
secant as a tangent.
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# They should understand that a tangent is always perpendicular to the radius of the circle.
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# They should know construction of a tangent to a given point.
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# If the same straight line is a tangent to two or more circles, then it is called a common tangent.
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# If the centres of the circles lie on the same side of the common tangent, then the tangent is called a direct common tangent.
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# Note: In general,
 +
*The two circles are named as C1 and C2
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* The distance between the centre of two circles is 'd'
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* Radius of one circle is taken as 'R' and other as 'r'
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* The length of tangent is 't'
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*Multimedia resources: Laptop
 
*Website interactives/ links/ / Geogebra Applets
 
*Website interactives/ links/ / Geogebra Applets
*Process/ Developmental Questions
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*Process:
*Evaluation
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[Note for  teachers : Evaluate if it is possible to construct a direct common tangent without the third circle.]<br>
*Question Corner
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The teacher can explain the step by step construction of Direct common tangent  and with an example
 +
*Developmental Questions:
 +
# What is a tangent
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# What is a common tangent ?
 +
# What is a direct common tangent ?
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# What is R and r  ?
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# What does the length OA represent here ?
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# Why was a third circle constructed ?
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# Let us try to construct direct common tangent without the third circle and see.
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# What should be the radius of the third circle ?
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# Why was OA bisected and semi circle constructed ?
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# What were OB and OC extended ?
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# What can you say about lines AB and AC ?
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# Name the direct common tangents .
 +
# At what points is the tangent touching the circles ?
 +
# Identify the two right angled triangles formed from the figure ? What do you understand ?
 +
*Evaluation:
 +
# Is the student able to comprehend the sequence of steps in constructing the tangent.
 +
# Is the student able to identify error areas while constructing ?
 +
# Is the student observing that the angle between the tangent and radius at the point of intersection is 90º ?
 +
# Is the student able to appreciate that the direct common tangents from the same external point are equal and subtend equal angles at the center.
 +
*Question Corner:
 +
# What do you think are the applications of tangent constructions ?
 +
# What is the formula to find the length of direct common tangent ?
 +
# Can a direct common tangent be drawn to two circles one inside the other ? 
 +
# Observe the point of intersection of extended tangents in relation with the centres of two circles. Infer.
 +
# What are properties of direct common tangents ?
 +
 
 
===Activity No # ===
 
===Activity No # ===
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Question Corner
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==Concept #3. Construction of direct common tangent.==
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===Learning objectives===
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Evaluation
 
*Question Corner
 
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==Concept #4. Construction of transverse common tangent.==
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===Learning objectives===
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===Notes for teachers===
 
===Activity No # ===
 
===Activity No # ===
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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{| style="height:10px; float:right; align:center;"
 
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''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
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*Evaluation
 
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*Question Corner
 
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==Concept #3. Construction of direct common tangent.==
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===Learning objectives===
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===Notes for teachers===
   
===Activity No # ===
 
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{| style="height:10px; float:right; align:center;"
 
{| style="height:10px; float:right; align:center;"
 
|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
 
|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
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===Activity No # ===
 
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|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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===Activity No # ===
 
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|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
 
|<div style="width:150px;border:none; border-radius:10px;box-shadow: 5px 5px 5px #888888; background:#f5f5f5; vertical-align:top; text-align:center; padding:5px;">
''[http://www.karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
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''[http://karnatakaeducation.org.in/?q=node/305 Click to Comment]''</div>
 
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*Estimated Time
 
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*Question Corner
 
*Question Corner
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= Hints for difficult problems =
 
= Hints for difficult problems =
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Create a new page and type <nowiki>{{subst:Math-Content}}</nowiki> to use this template
 
Create a new page and type <nowiki>{{subst:Math-Content}}</nowiki> to use this template
 +
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[[Category:Circles]]

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