What is the value of x?

This is an isosceles triangle because the picture shows it has two equal sides. Isosceles triangles have two equal angles.
The sum of all the angles of a triangle = 180º.
We can use this equation to solve for x:
2x + 54 = 180.
- 54 -54 Subtract 54 from both sides.
2x = 126
/ 2 /2 Divide 2 from both sides to isolate x.
x = 63º
Let's check! 63 + 63 + 54 = 180? YUP!