A parallelogram has an interior angle measuring 81º. Which MUST also be the measure of an interior angle of the

parallelogram?

A) 9°. C) 49°

B) 19° D) 99°

D) 99 degrees

Step-by-step explanation:

The answer is D. All the angles in any quadrilateral add up to 360 degrees. And since the figure is a paralledlogram, for each angle there is another angle with the same measurement. So 81 + 81 + x + x = 360 which gives us 162 + 2x = 360. If you solve for x you get 99 degrees.