Answer:
The answer is 7
Explanation:
You are absolutely right. The angles of a triangle need to add up to 180 so from the picture we can create the following equation:
90 + 30 + 8x + 4 = 180 (adding together numbers)
124 + 8x = 180 (subtracting 124 from both sides to maintain equality)
124 - 124 + 8x = 180 - 124
8x = 56 (dividing by 8 both sides to isolate x)
(8*x)/8 = 56/8
x = 7