Answer: 54°
Explanation:
We can see that this triangle is a right triangle (look at the little square in the triangle's corner-- that tells us that it's a right angle). A right angle is 90°
A triangle always has 180° in total.
So, we can add 90° and 36° and subtract the sum from 180°
180° - (90° + 36°) = 180° - 126° = 54°