Complementary
and Supplementary Angles
Section A: Unit Notes
Complementary
Angles
Two angles are complementary when they add up to 90 degrees. (right angle)
These two angles (40° and 50°) are Complementary
Angles because they add up to 90°:
Supplementary
Angles
Two angles are supplementary when they add up to 180 degrees.
These two angles (140° and 40°) are Supplementary
Angles because they add up to 180°:
How to
remember which is which? Well, alphabetically, they are:
- Complementary add
to 90°
- Supplementary add
to 180°
Section B: Video Lesson
To better understand complementary and supplementary angles…click
the video below.
Section C:
Online Module
Complementary and Supplementary Angles| School Yourself Geometry