because if you notice, each of the angles have a little arc in the corner, which means they are congruent. if all three angles are congruent, that means each angle is 60° because each triangle has a maximum value of 180°. therefore, this means it is an equilateral triangle.
that being said, each side must be equal as well. so, you can use any two sides to find x by using each one on a different side of an equation, then isolating and solving.
