Complementary Meaning?

In the app below, the two colored angles are said to be complementary angles.

Interact with this app for a few minutes. LARGE POINTS are moveable.

In your own words, describe what you think it means for 2 angles to be complementary.

In the app above, one colored angle is said to be the complement of the other colored angle, and vice versa. Given this information, determine the complement of a 40 degree angle.

What is the complement of an angle that measures 1 degree?

What angle has a measure whose complement is equal to itself?