Question

In the given figure, sides AD and AB of cyclic quadrilateral ABCD are produced to E and F respectively. If ∠CBF = 130° and ∠CDE = x°, find the value of x.

Answer 1

In a cyclic quadrilateral we know that the exterior angle is equal to the interior opposite angle

So we get

∠CBF = ∠CDA

It can be written as

130^o = 180^o – x

On further calculation

x = 180^o – 130^o

By subtraction

x = 50^o