If a right triangle has an angle that is 55°

In a triangle, the sum of the angles is always 180°. In a right triangle, one of the angles is 90°. Therefore, to find the measure of the third angle, you can use the following calculation:

1. The sum of the angles in the triangle: 180°
2. The known angles: 90° (right angle) and 55° (given angle)

Now, you can calculate the measure of the third angle:

\( 180° - 90° - 55° = 35° \)

So, the measure of the third angle is **35°**.