The correct answer to your question is that the two angles that give the same range are complementary, meaning they add up to 90 degrees.
This relationship arises from the physics of projectile motion. Specifically, if you have two angles \( \theta_1 \) and \( \theta_2 \) such that:
\[ \theta_1 + \theta_2 = 90^\circ \]
and both are set to the same launch speed, they will yield the same horizontal range when launched from the same height. This is because of the symmetrical nature of projectile motion in uniform gravity when considering angle and speed.
So, the best answer is: They are complementary (add to 90 degrees).