how are 48 angle and the 90 angle related?

Question

a kite string makes an angle of 48 with respect to  the ground as shown below. the dashed line is vertical and the grounnd is horizontal. How are 48 angle and the unkniw angle related? What is the value of x?

Answer 1

The unknown angle is 90-48=42 degrees, because the angles in a triangle must add up to 180 degrees. We already have two of them, 48 and 90, so the third angle is 180-(90+48) which is the same as (180-90)-48=90-48. The acute angles are said to be complementary.