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Year 8 Angles in Polygons Worksheet — Level 1 — Practice Set 3 — Answers

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Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Angles

Year 8 Angles in Polygons Worksheet — Level 1 — Practice Set 3 — 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 a nonagon.

Answer: 1,260°

  1. Angle sum = (n − 2) × 180°
  2. (9 − 2) × 180° = 1,260°
2.Find the size of each interior angle of a regular 36-sided polygon.

Answer: 170°

  1. Angle sum = (36 − 2) × 180° = 6,120°
  2. 6,120° ÷ 36 = 170°
3.Find the sum of the interior angles of a 20-sided polygon.

Answer: 3,240°

  1. Angle sum = (n − 2) × 180°
  2. (20 − 2) × 180° = 3,240°
4.Find the size of each interior angle of a regular 15-sided polygon.

Answer: 156°

  1. Angle sum = (15 − 2) × 180° = 2,340°
  2. 2,340° ÷ 15 = 156°
5.Find the sum of the interior angles of a hexagon.

Answer: 720°

  1. Angle sum = (n − 2) × 180°
  2. (6 − 2) × 180° = 720°
6.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°
7.Find the sum of the interior angles of a 15-sided polygon.

Answer: 2,340°

  1. Angle sum = (n − 2) × 180°
  2. (15 − 2) × 180° = 2,340°
8.Find the size of each interior angle of a regular 18-sided polygon.

Answer: 160°

  1. Angle sum = (18 − 2) × 180° = 2,880°
  2. 2,880° ÷ 18 = 160°
9.Find the sum of the interior angles of a heptagon.

Answer: 900°

  1. Angle sum = (n − 2) × 180°
  2. (7 − 2) × 180° = 900°
10.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°
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