Question

In cyclic quadrilateral ABCD m∠A = 100°, then find m∠C.

Answer 1

In `square`ABCD, m∠A = 100°

As `square`ABCD is a cyclic quadrilateral.

∴ By using cyclic quadrilateral theorem,

m∠A + m∠C = 180°   

100° + m∠C = 180°

m∠C = 180° − 100°

m∠C = 80°