Answer:
![\huge\boxed{\sf x = 20}](https://img.qammunity.org/2021/formulas/mathematics/high-school/rrgv42c29vk6u08zurhl2v8wrtdjb0bxzl.png)
Explanation:
=> Since it is an equilateral (Having all angles and all sides equal) triangle, so every angles will be equal to the other.
=> The sum of the measures of interior angles of triangle add up to 180 degrees.
So,
3x + 3x + 3x = 180
9x = 180
Divide both sides by 9
x = 20
![\rule[225]{225}{2}](https://img.qammunity.org/2021/formulas/chemistry/middle-school/ri1osubq0ul0fyszs3s2hvchlv85n22xxb.png)
Hope this helped!
~AH1807