In this page we practice using the rule:
Exterior angle = sum of the two remote interior angles
Example 1
Remote interior angles are:
80° and 30°
Exterior angle = 80 + 30
Exterior angle = 110°
Example 2
Exterior angle = 60°
One remote interior angle = 40°
Other angle = x
x + 40 = 60
x = 20°
Example 3
Exterior angle = 100°
Remote interior angles are x and x
x + x = 100
2x = 100
x = 50°
Example 4
Exterior angle = 7x
Remote interior angles are:
2x + 3 and 6x − 13
(2x + 3) + (6x − 13) = 7x
8x − 10 = 7x
x = 10
Now find the angles:
First angle = 2(10) + 3 = 23°
Second angle = 6(10) − 13 = 47°
Exterior angle = 7(10) = 70°
Practice
- More Examples
Continue Learning
- Types of Triangles
- Triangles (Basics)
- Sum of Angles of a Triangle is 180° (Proof)
- Find the Missing Angle of a Triangle
- Sum of Exterior Angles of a Triangle (Proof)
- Exterior Angle Theorem of a Triangle
- Two Exterior Angles at a Vertex are Equal (Proof)
- Two Exterior Angles are Equal at a Vertex (Quick Proof)