Answer:
a
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Sum the 3 angles and equate to 180
x + 18 + 4x + 112 = 180 , collect like terms
5x + 130 = 180 ( subtract 130 from both sides )
5x = 50 ( divide both sides by 5 )
x = 10
