In the image, I see a triangle with one labeled angle of $72^\circ$ and an adjacent line with an indicated angle of $90^\circ$, likely suggesting a right angle. This seems to indicate a right triangle with a 90-degree angle, and the 72-degree angle is one of the non-right angles.

To find the remaining angle in the triangle, we use the fact that the sum of angles in a triangle is always $180^\circ$. Therefore, the missing angle, $x$, can be calculated as follows:

$x = 180^\circ - 90^\circ - 72^\circ = 18^\circ$

Thus, the remaining angle in the triangle is $18^\circ$.

Would you like a more detailed explanation or have any other questions about this?

Here are 5 related questions to think about:

1. How can you calculate the side lengths of this right triangle if one of the sides is known?
2. What is the sine, cosine, or tangent of the 72° angle in this triangle?
3. How would the triangle change if the 72° angle were altered to another value?
4. Can you identify other types of triangles based on their angle properties (e.g., equilateral or isosceles)?
5. What are the uses of the Pythagorean theorem in right triangles like this one?

Tip: The sum of interior angles in any triangle always adds up to $180^\circ$, which is helpful for solving many types of triangle-related problems.