Question

Quadrilateral ABCD is inscribed in a circle. What is the measure of angle A?

Answer 1

`133^o`

Explanation:

the quadrilateral is a cyclic quadrilateral, and its fundamental property is that the opposite angles are supplementary

ie they add up to `180^o`

`:.4x+5+x+15=180`

`5x+20=180`

`5x=180-20=160`

`x=160/5=32`

`:. < A=4xx32+5=128+5=133`