Question

In a cyclic quadrilateral ABCD, if angle A is 100° what is the measure of angle C?

• A. 100°
• B. 80°
• C. 90°
• D. 70°

Answer 1

Answer:

B. 80°

In a cyclic quadrilateral, opposite angles are supplementary.

So,

$\angle A + \angle C = 180^\circ$

Given:

$\angle A = 100^\circ$

Therefore,

$\angle C = 180^\circ - 100^\circ = 80^\circ$
So, the measure of angle (C) is:

$\boxed{80^\circ}$