Quadrilateral abcd is inscribed in a circle with m∠a = (x) degrees, m∠b = (2x - 10) degrees, and m∠c = (3x) degree. what is m∠d?

A. 45 degrees

B. 135 degrees

C. 100 degrees

D. 80 degrees

Hello,

When you have a polygon inscribed in a circle, the opposite angles are supplementary.

So we can start by saying that A + C = 180. Or x + 3x = 180. This gives us a value of 45 for x.

If we input that in for angle B, we get: 2 (25) - 10 = 80.

If angle B = 80, then angle D must be 100, because the angles are supplementary.

Good luck,

MrEQ