Exterior Angles Of A Triangle

In this lesson, we will look at the property of the exterior angles of a triangle and how it can be used to find a missing angles.

An exterior angle of a triangle is equal to the sum of the two opposite interior angles.

Example :

Example :

Find the values of x and y in the following triangle.

Solution:

x + 50° = 92° (sum of opposite interior angles = exterior angle)

x = 92° – 50°

= 42°

y + 92° = 180° (interior angle + adjacent exterior angle = 180°.)

y = 180° – 92°

= 88°

The following video shows an example of how to find the exterior angle of a triangle.

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