Angle Geometry
On this page you will learn about:
- Classifying single angles
- Classifying pairs of angles
- Finding the value of a missing angle
- Check your understanding
Classifying Angles
An angle describes an amount of turn or rotation, and is measured in degrees (°). (1)
One complete turn or revolution is 360°
A protractor, like the one below, can be used to measure the size of any angle.
One complete turn or revolution is 360°
A protractor, like the one below, can be used to measure the size of any angle.
Complementary Angles
Supplementary Angles
Adjacent Angles
Vertically Opposite Angles
Vertically Opposite Angles occur when two straight lines cross each other. The result is two pairs of equal angles that are opposite each other.
(5)
(5)
Using Angle Geometry to Find Missing Values
Find the missing variable, and give reasons.
Find the missing variable, and give reasons.
Find the missing variable, and give reasons.
a=110, because a is vertically opposite 110°.
b=70, because b is supplementary to 110° and therefore adds to 180°.
(5)
b=70, because b is supplementary to 110° and therefore adds to 180°.
(5)