Question

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

Answer 1

Answer:

Quadrilateral ABCD is inscribed in a circle, then

A + C = 180

=> 2x + 9 + 3x + 1 = 180

=> 5x = 170

=> x = 34

=> A  = 2 x 34 + 9 = 77 deg

Hope this helps!

:)

Answer 2

Answer:

77°

Step-by-step explanation:

ABCD is inscribed in a circle. Therefore it is a cyclic quadrilateral. Opposite angles of a cyclic quadrilateral are supplementary.

$\therefore \angle A + \angle C = 180° \\ (2x + 9) \degree + (3x + 1) \degree =180° \\ (5x + 10) \degree =180° \\ 5x + 10 = 180 \\ 5x = 180 - 10 \\ 5x = 170 \\ x = \frac{170}{5} \\ x = 34 \\ \angle A = (2 \times 34 + 9) \degree \\ \huge \red{ \boxed{\angle A= 77 \degree}}$