This is an isosceles triangle, as you can know by the fact that two of its sides have the same length.
This kind of triangle has the particularity that the two angles next to the side which has a different value, are the same.
In this case, x is equal to the angle that has no name
Moreover, in a triangle, the sum of its angles is equal to 180°
So, we have that: 2x+46°=180° and we only need to solve this equation
We divide both sides of the equation by 2
->x+23°=90°
Subtract 23° on both sides of the equation:
->x=90°-23°=67°