Answer:
m∠C = 122°
Step-by-step explanation:
Opposite angles of a quadrilateral inscribed in a circle are supplementary. This means
m∠A + m∠C = 180°
m∠B + m∠D = 180°
To find angle C we need to find x, then subtract m∠A from 180°
x+20=3x
20=2x
x=10
Now we substitute 10 in for x
m∠A=2(10)+38
m∠A=20+38
m∠A=58°
Now we subtract this value from 180.
m∠C=180-58
m∠C=122°
