Answer:
X = 4
Explanation:
The angles of a triangle add up to 180 degrees and this is an equilateral triangle which means that all the angles are the same. which means you set up the equation:
10x + 20 + 10x + 20 + 10x + 20 = 180
Simplify: 30x + 60 = 180
- 60 - 60
You have : 30x = 120
(Divide by 30)
You end up with: X = 4