Answer: True
Step-by-step explanation:
A supplementary angle refers to the angles that has a sum of 180° when they're added together.
We should note that a right angle equals to 90°, therefore the other angle in the supplementary angle will be:
= 180° - 90°
= 90°
Since a right angle equals 90°, then the other angle must be a right angle.
Therefore, the answer is TRUE.
