Hey there! :)
Answer:
C. m∠x = 35°.
Step-by-step explanation:
Begin by finding the value of the third angle of the triangle. Recall that all interior angles of a triangle sum up to 180°:
180 - 73 - 51 = 56°.
Since the top angle is split into x and 21°, simply subtract to solve for x:
56 - 21 = 35°. Therefore:
m∠x = 35°.
