Two angles are Complementary when they These two angles (40° and 50°) are Complementary Angles, because they add up to 90°: Notice that together they make a right angle But the angles don't have to be together. These two are complementary because 27° + 63° = 90° (Drag the points) images/geom-comp-supp.js?mode=comp
Right Angled TriangleIn a right angled triangle, the two non-right angles are complementary, because in a triangle the three angles add to 180°, and 90° has already been taken by the right angle. When two angles add to 90°, we say they "Complement" each other. Spelling: be careful, it is not "Complimentary Angle" (with an "i") ... Complementary vs SupplementaryA related idea is Supplementary Angles - those add up to 180°
How to remember which is which? Well, alphabetically they are:
You can also think:
Or you can think:
5231, 5233, 819, 2109, 820, 2110, 5240, 9063, 3305, 3306 Copyright © 2022 Rod Pierce
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