What are the angles in a 45° triangle?

In a triangle with one angle measuring 45 degrees, it is known as an isosceles right triangle if it has another angle of 45 degrees, which would make the third angle 90 degrees. The sum of the angles in any triangle is always 180 degrees. Therefore, if two angles are each 45 degrees, their total is 90 degrees, leaving the remaining angle, being the right angle, to measure 90 degrees.

This configuration is common in both geometry and trigonometry and can be useful in various applications, such as calculating lengths using trigonometric ratios or understanding properties of triangles in a coordinate system. The choice representing angles of 30 degrees and 60 degrees, or 90 degrees and 30 degrees, refers to different well-known triangles and does not fit the specified conditions of having an angle at 45 degrees. The isosceles property further solidifies that the two equal angles must both be 45 degrees.