This is circle based question from Chapter name- circles

Topic – Angle properties of circles

Chapter number- 15

It is given that , O is the centre of the circle and AB is a tangent at B. If AB = 15 cm and AC = 7.5 cm,

Then we have to find the radius of the circle. (b) In the figure given , from an external point P, tangents PA and PB are drawn to a circle.

It is also given that CE is a tangent to the circle at D. If AP = 15 cm,Â now we have to find the perimeter of the triangle PEC.

ICSE Avichal publication

Understanding ICSE Mathematics

Question no 8

Solution:(i) Join OB

âˆ OBA = 90Â°

(Radius through the point of contact is

perpendicular to the tangent)