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Year 8 Angles in Polygons Worksheet — Level 2 — Practice Set 3 — Answers

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Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Angles

Year 8 Angles in Polygons Worksheet — Level 2 — 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 dodecagon.

Answer: 1,800°

  1. Angle sum = (n − 2) × 180°
  2. (12 − 2) × 180° = 1,800°
2.Find the size of each interior angle of a regular nonagon.

Answer: 140°

  1. Angle sum = (9 − 2) × 180° = 1,260°
  2. 1,260° ÷ 9 = 140°
3.Find the size of each exterior angle of a regular hexagon.

Answer: 60°

  1. Exterior angles add to 360°
  2. 360° ÷ 6 = 60°
4.Each exterior angle of a regular polygon is 72°. How many sides does it have?

Answer: 5

  1. Exterior angles add to 360°
  2. 360 ÷ 72 = 5 sides
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 36-sided polygon.

Answer: 170°

  1. Angle sum = (36 − 2) × 180° = 6,120°
  2. 6,120° ÷ 36 = 170°
7.Find the size of each exterior angle of a regular pentagon.

Answer: 72°

  1. Exterior angles add to 360°
  2. 360° ÷ 5 = 72°
8.Each exterior angle of a regular polygon is 12°. How many sides does it have?

Answer: 30

  1. Exterior angles add to 360°
  2. 360 ÷ 12 = 30 sides
9.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°
10.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°
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