Question

A triangle is 180 degrees. One angle is x degrees and the second angle is 77 degrees. What is the expression that shows the measure of the third angle in degrees?

My guess is B.

A. 180 + x + 77
B. 180 - x + 77
C. 180 + x - 77
D. 180 - x - 77

Answer 1

Every triangle's angles sum to 180°
angle1 + ang2 + ang3 = 180 °
So if we want to find ang3, the formula would be
ang3 = 180 -ang1 - ang2
That should give you a good hint (and the answer is not B)

Answer 2

D?

Answer 3

very good !!

Answer 4

Thank you for explaining!

Answer 5

it's good to see that an explanation is better than just posting an answer.