Geometry and measuresKey Stage 3

Number of sides of a regular polygon

Use polygon angle facts to find missing values.

  • One interior angle and its adjacent exterior angle add to .
  • Number of sides: .

Example 1

A regular polygon has the marked angle. How many sides does it have?

First find one exterior angle.
First find one exterior angle.

Example 2

A regular polygon has the marked angle. How many sides does it have?

Divide one complete turn by one exterior angle.

Your turn

Question 1

A regular polygon has the marked angle. How many sides does it have?

Check answer
First find one exterior angle.
First find one exterior angle.
Question 2

A regular polygon has the marked angle. How many sides does it have?

Check answer
Divide one complete turn by one exterior angle.
Question 3

A regular polygon has the marked angle. How many sides does it have?

Check answer
First find one exterior angle.
First find one exterior angle.
Question 4

A regular polygon has the marked angle. How many sides does it have?

Check answer
Divide one complete turn by one exterior angle.
Question 5

A regular polygon has the marked angle. How many sides does it have?

Check answer
First find one exterior angle.
First find one exterior angle.
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