SAT Math Multiple Choice Practice Question 454: Answer and Explanation
16. If the average measure of two angles in a parallelogram is y , what is the average degree measure of the other two angles?
A. 180 – y
B. 180 -
C. 360 – 2y
D. 360 + y
Correct Answer: A
A Let's begin by drawing a parallelogram and plugging in a number for y, say 50, and calling the other two angles x:
Because there are 360 degrees in a quadrilateral, you know that 2x + 100° = 360°, which means x = 130°. So, you're looking for the choice that gives you 130 when y = 50°. You simply plug 50 into all of the answer choices to find that A is the only one that works.