Answer:
45°
Step-by-step explanation:
The sum of interior angles in a triangle is equal to 180°
60 + x + 87 + x + 57 = 180 add like terms
2x + 204 = 180 subtract 204 from both sides
2x = -24 divide both sides by 2
x = -12
angle A is x + 57 so if we replace A with the value we found
(-12) + 57 = 45°
