The Isosceles Triangle Theorem states that in an isosceles triangle, the angles opposite the two equal sides are congruent.

To find the value of $x$, we need more information about the triangle (like its angles or side lengths). You mentioned "10" and "x," which could represent side lengths, but I would need more details to solve this correctly.

Could you please clarify the specific values or provide more details about the triangle?

Feel free to upload an image if that helps!

Here are 5 related questions to expand your understanding:

1. How do you identify the congruent angles in an isosceles triangle?
2. Can the base angles of an isosceles triangle be different?
3. How can the Isosceles Triangle Theorem be applied in right triangles?
4. What happens if the vertex angle is known but the base angles are unknown?
5. How do you solve for unknown side lengths using the Isosceles Triangle Theorem?

Tip:

When solving for unknowns in a triangle, always check if the triangle has any symmetry properties (like being isosceles or equilateral). This can significantly simplify calculations.