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The longest chord passes through the centre of the circle (view source)
Revision as of 12:22, 4 December 2013
, 12:22, 4 December 2013→Concept # Cyclic quadrilateral
# The teacher can recall the concept of a circle, quadrilateral, circumcircle.
# The teacher can recall the concept of a circle, quadrilateral, circumcircle.
# Can explain a cyclic quadrilateral and show the geogebra applet.
# Can explain a cyclic quadrilateral and show the geogebra applet.
# Move points, the vertices of the quadrilateral and let the students observe the opposite interior angles.
# Move points, the vertices of the quadrilateral and let the students observe the sum of opposite interior angles.
Developmental Questions:
Developmental Questions:
# What two figures do you see in the figure ?
# What two figures do you see in the figure ?
# Name the vertices of the triangle.
# Name the vertices of the quadrilateral.
# Where are all the 4 vertices situated ?
# Where are all the 4 vertices situated ?
# Name the opposite interior angles of the quadrilateral.
# Name the opposite interior angles of the quadrilateral.
*Prerequisites/Instructions, if any
*Prerequisites/Instructions, if any
# The students should know a circle and a quadrilateral.
# The students should know a circle and a quadrilateral.
# They should follow the instructions carefully.
# They should know that in a cyclic quadrilateral the sum of opposite interior angles is 180 degrees.
# In a cyclic quadrilateral the exterior angle is equal to interior opposite angle
*Multimedia resources
*Multimedia resources
*Website interactives/ links/ / Geogebra Applets
*Website interactives/ links/ / Geogebra Applets
This activity has been taken from the website http://mykhmsmathclass.blogspot.in/2007/11/class-ix-activity-16.html
*Process:
*Process:
# Draw a circle of any radius on a coloured paper and cut it.
# Draw a circle of any radius on a coloured paper and cut it.
# Produce AB to form a ray AE such that exterior angle CBE is formed.
# Produce AB to form a ray AE such that exterior angle CBE is formed.
# Make a replica of angle ADC and place it on angle CBE . Write the observation.
# Make a replica of angle ADC and place it on angle CBE . Write the observation.
Developmental Questions:
# How do you take radius ?
# What is the circumference ?
# What is a chord ?
# What is a quadrilateral ?
# Where are all four vertices of a quadrilateral located ?
# What part are we trying to cut and compare ?
*Evaluation
# What can you infer ?
*Question Corner
*Evaluation:
# Angle BAD and angle BCD, when placed adjacent to each other on a straight line, completely cover the straight angle.What does this mean ?
# Angle ABC and angle ADC, when placed adjacent to each other on a straight line, completely cover the straight angle.What can you conclude ?
# Compare angle ADC with angle CBE.
*Question Corner:
Name the two properties of cyclic quarilaterals.
= Hints for difficult problems =
= Hints for difficult problems =
