Answer:
∠x = 60°
Explanation:
first:
∠a = 60° was given
the sides on each side of ∠a are equal so their opposite angles are equal also.
The sum of the interior angles of any triangle is 180°
The angles opposite ∠a are (180° - 60°)/2 = 60° each
Second:
∠b = 60° was given
so the angles opposite ∠b are also 60° each
Third:
the 2 angles opposite x are both 60° each because they are both vertical angles to 60°
That leaves ∠x to be 180° - 60° - 60° = 60°