One of the most important and exam oriented question from Chapter name- circles

Topic – Angle properties of circles

Chapter number- 15

This question has been asked in 1994.

In this question we have been given that , O is the centre of the circumcircle of triangle XYZ.

Two tangents at X and Y intersect at T.

Also it is given ∠XTY = 80° and ∠XOZ = 140°, now we have to calculate the value of ∠ZXY.

ICSE Avichal publication

Understanding ICSE Mathematics

Question 28(a)

Solution:-

Join OY, OX and OY are the radii of the circle

and XT and YT are the tangents to the circle.

<ZXY=1/2(<ZOY)=120/2=60