Anonymous

Changes

From Karnataka Open Educational Resources
688 bytes added ,  09:26, 12 August 2014
Line 167: Line 167:  
#Tanjents AP and AQ are drawn to circle with centre O, from an external point A. Prove that  ∠PAQ=2.∠ OPQ <br>
 
#Tanjents AP and AQ are drawn to circle with centre O, from an external point A. Prove that  ∠PAQ=2.∠ OPQ <br>
 
[[File:fig1.png|200px]]
 
[[File:fig1.png|200px]]
 +
===Interpretation of the problem===
 +
#O is the centre of the circle and tangents AP and AQ are drawn from an external point A.
 +
#OP and OQ are the radii.
 +
#The students have to prove thne angle PAQ=twise the angle OPQ.
 +
===Concepts used.===
 +
#The radii of a circle are equal.
 +
#In any circle the radius drawn at the point of contact is perpendicular to the tangent.
 +
#The tangent drawn from an external point to a circle a] are equal b] subtend equal  angle at the centre c] are equally inclined to the line joining the centre and extrnal point.
 +
#Properties of isoscles triangle.
 +
#Properties of quadrillateral ( sum of all angles) is 360 degrees
 +
#Sum of three angles of triangle is 180 degrees.
    
== Ex 4.4.2==
 
== Ex 4.4.2==