# Exterior angles

## Lesson details

### Key learning points

1. In this lesson, we will learn about exterior angles, and how they sum to 360 degrees.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

## Video

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## Worksheet

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## Starter quiz

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### 5 Questions

Q1.
A triangle is made up of the following: 73 degrees, 51 degrees and x degrees. Solve for x.
180 degrees
236 degrees
65 degrees
Q2.
If a quadrilateral contains 3 right angles, what must the final angle be to form a quadrilateral?
A reflex angle
An acute angle
An obtuse angle
Q3.
If the angles in a decagon are the following: 73 degrees, 293 degrees, 203 degrees, 9 degrees, 29 degrees, 184 degrees, 173 degrees, 93 degrees, 208 degrees, y degrees. Solve for y.
295
75
95
Q4.
Is it possible to have two obtuse angles in a triangle?
Yes
Q5.
You are told that V + W + X + Y + Z = total interior sum of a pentagon. If V = 90 degrees, W = 110 degrees, X = 10 degrees, Y = 300 degrees, what would Z be?
210
3
300

## Exit quiz

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### 5 Questions

Q1.
The total exterior angles of a polygon sum to...
180 degrees
720 degrees
90 degrees
Q2.
Which of the following most closely matches the definition of an "exterior angle"?
An angle that is between 180-360 degrees
Correct answer: The angle between a side of a polygon, and an adjacent side extended outward.
The angle on the inside of a polygon.
The angle on the outside of a polygon, often being reflex.
Q3.
If an interior angle is 103 degrees, then the exterior angle would be...
13 degrees
257 degrees
Impossible to tell; there's not enough information.
Q4.
If an exterior angle is 15 degrees, then the interior angle would be...
15 degrees
345 degrees
85 degrees
Q5.
If I wanted to find the exterior angle of a regular n-sided polygon, which formula should I follow?
180(n-2)
180/n
360(n-2)/n