Question

Find the missing angle measure in QRS.
Q = _____°, R = 60°, S = 20°
A. 80
B. 100
C. 120
D. 60

Answer 1

R+S+Q=180
60+20+Q=180
Q=180-80=100

Answer 2

sum of three angles in a triangle is 180 degrees

Answer 3

The interior angles of a polygon with n sides add up to (n-2)*180 (degrees). This is a triangle, 3 sides, n = 3, so the sum of the interior angles is (3-2)*180 degrees. You've already got 60+20 = 80 degrees accounted for, so the remaining angle is 180 degrees - 80 degrees = 100 degrees

Answer 4

With a rectangle, there are 4 sides, so n = 4, and the interior angles add up to 2*180 degrees = 360 degrees.

Answer 5

thanks!