This is a triangle with two angles provided: $76^\circ$ and $55^\circ$. The unknown angle is labeled as $x^\circ$.

Using the triangle sum theorem, we know that the sum of all interior angles of a triangle is always $180^\circ$. Therefore, to find $x$, we can use the following formula:

$x^\circ = 180^\circ - 76^\circ - 55^\circ$

Calculating:

$x^\circ = 180^\circ - 131^\circ = 49^\circ$

Thus, the value of $x$ is $49^\circ$.

Do you want more details or have any questions?

Here are 5 related questions to deepen your understanding:

1. What is the triangle sum theorem?
2. Can the sum of any triangle's angles ever be more or less than 180 degrees?
3. How do you find an unknown angle if only two angles are provided?
4. What are the different types of triangles based on angles?
5. How do you classify a triangle with angles $55^\circ$, $76^\circ$, and $49^\circ$?

Tip: Always remember that the sum of angles in a triangle is $180^\circ$, which can help you find missing angles quickly!