Answer:
A. 21
Step-by-step explanation:
Recall: inscribed angle in a semicircle equals 90°
m<K is an inscribed angle in a semicircle = (4x + 6)°
Therefore,
4x + 6 = 90°
Solve for x. Subtract both sides by 6
4x + 6 - 6 = 90 - 6
4x = 84
Divide both sides by 4
4x/4 = 84/4
x = 21
