Find the outer angle at the third vertex of the triangle if its two angles are equal: 54 and 36 (degrees).

A triangle is a figure consisting of three points that do not lie on one straight line and are connected by segments.

According to the properties of a triangle, the sum of all its angles is 180 °. In this way:

∠С = 180 ° – ∠А – ∠В;

∠С = 180 ° – 54 ° – 36 ° = 90 °.

The outside angle at the apex of a triangle is the angle adjacent to the vertex. Together they make up an unfolded angle that is 180 °.

Based on this:

φ = 180 ° – ∠С;

φ = 180 ° – 90 ° = 90 °.

Answer: the outer angle of the triangle at the vertex ∠С is equal to 90 °