Answer:
D. Angle addition postulate
Explanation:
The angle addition postulate tells you the larger angle SQP is the sum of the angles produced by the dividing ray OR. That is, ...
∠SQR +∠PQR =∠SQP
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Then the subtraction property of equality is used to find the value of ∠PQR:
∠PQR = ∠SQP -∠SQR . . . . . subtract ∠SQR from both sides
∠PQR = 160° -20° = 140°