Geometry and measuresKey Stage 3

Interior angles of an irregular polygon

Use polygon angle facts to find missing values.

  • Use for the total.
  • Subtract all the known interior angles. Do not assume the angles are equal.

Example 1

Find angle .

Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.

Example 2

Find angle .

Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.

Your turn

Question 1

Find angle .

Check answer
Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.
Question 2

Find angle .

Check answer
Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.
Question 3

Find angle .

Check answer
Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.
Question 4

Find angle .

Check answer
Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.
Question 5

Find angle .

Check answer
Use the number of sides to find the angle sum.
Use the number of sides to find the angle sum.
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