Question

question 8 of 10 given ▱pqrs and ∠s = 40°, what is the measure of ∠r? a. 140° b. 135° c. 90° d. 105° e. 40° f. cannot be determined

Explanation:

Step1: Recall property of parallelogram

Adjacent angles of parallelogram are supplementary.

Step2: Set up angle - sum equation

\(\angle S+\angle R = 180^{\circ}\).

Step3: Solve for \(\angle R\)

\(\angle R=180^{\circ}-\angle S\). Since \(\angle S = 40^{\circ}\), then \(\angle R=180 - 40=140^{\circ}\).

Answer:

A. 140°