This is a triangle where one angle is given as $40^\circ$, and the other two angles are marked as $x^\circ$. Since the sum of angles in any triangle is always $180^\circ$, we can set up the following equation:

$40^\circ + x^\circ + x^\circ = 180^\circ$

Simplifying this:

$40^\circ + 2x = 180^\circ$

Subtracting $40^\circ$ from both sides:

$2x = 140^\circ$

Now, divide by 2:

$x = 70^\circ$

Thus, the value of $x$ is $70^\circ$.

Let me know if you want further details or have any questions!

Here are some related questions:

1. How can you find the angles of an isosceles triangle?
2. What is the sum of the angles in any polygon?
3. How does the concept of symmetry apply to isosceles triangles?
4. What are the types of triangles based on their angles?
5. How do you solve for an unknown angle in a right triangle?

Tip: In any triangle, knowing that the angles sum to $180^\circ$ is essential for solving unknown angles.