Answer:
to find the answer, you need to find the measure of the angle on the other side of the 142. and since it's a straight line, those two angles measures are =to 180 (they're supplementary angles). so the measure of that angle is 38 degrees. to find the measure of the remaining angle, you subtract the angle measures you already know from 180 (because the sum of interior angles in a triangle is 180.) to, the answer is:
180-90-38= 52 degrees or A