Answer:
132°
Step-by-step explanation:
first find the interior angle of the triangle.
the interior angle of a triangle is 180°
90°+42°+y°=180°
132°+y°=180°
y°=180°-132°
y°=48°
(y° represents the empty part).
angle on a straight line is equal to 180°
y°+x°=180°
48°+x°=180°
x°=180°-48°
x°=132°
