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Year 9 Angles in Polygons Worksheet — Level 1 — Practice Set 4 — Answers

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Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Angles

Year 9 Angles in Polygons Worksheet — Level 1 — Practice Set 4 — Answers

Interior angle sum = (n − 2) × 180°. The exterior angles of any convex polygon add to 360°.

1.Find the sum of the interior angles of an octagon.

Answer: 1,080°

  1. Angle sum = (n − 2) × 180°
  2. (8 − 2) × 180° = 1,080°
2.Find the size of each interior angle of a regular quadrilateral.

Answer: 90°

  1. Angle sum = (4 − 2) × 180° = 360°
  2. 360° ÷ 4 = 90°
3.Find the sum of the interior angles of a nonagon.

Answer: 1,260°

  1. Angle sum = (n − 2) × 180°
  2. (9 − 2) × 180° = 1,260°
4.Find the size of each interior angle of a regular hexagon.

Answer: 120°

  1. Angle sum = (6 − 2) × 180° = 720°
  2. 720° ÷ 6 = 120°
5.Find the sum of the interior angles of a 11-sided polygon.

Answer: 1,620°

  1. Angle sum = (n − 2) × 180°
  2. (11 − 2) × 180° = 1,620°
6.Find the size of each interior angle of a regular 30-sided polygon.

Answer: 168°

  1. Angle sum = (30 − 2) × 180° = 5,040°
  2. 5,040° ÷ 30 = 168°
7.Find the sum of the interior angles of a quadrilateral.

Answer: 360°

  1. Angle sum = (n − 2) × 180°
  2. (4 − 2) × 180° = 360°
8.Find the size of each interior angle of a regular 24-sided polygon.

Answer: 165°

  1. Angle sum = (24 − 2) × 180° = 3,960°
  2. 3,960° ÷ 24 = 165°
9.Find the sum of the interior angles of a 14-sided polygon.

Answer: 2,160°

  1. Angle sum = (n − 2) × 180°
  2. (14 − 2) × 180° = 2,160°
10.Find the size of each interior angle of a regular 20-sided polygon.

Answer: 162°

  1. Angle sum = (20 − 2) × 180° = 3,240°
  2. 3,240° ÷ 20 = 162°
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