## Elementary Geometry for College Students (7th Edition)

The sum of the measures of the angles in a triangle is equal to 180$^{\circ}$. If a triangle is right, then one angle measures 90$^{\circ}$. Therefore, the sum of the remaining angles must be 90$^{\circ}$, making them complimentary.
The sum of the acute angles in a right triangle is 90$^{\circ}$ so they are complimentary angles.