Year 8 Angles in Polygons Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 8 angles worksheet.
Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · AnglesYear 8 Angles in Polygons Worksheet — Level 2 — Practice Set 2 — 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 quadrilateral.
Answer: 360°
- Angle sum = (n − 2) × 180°
- (4 − 2) × 180° = 360°
2.Find the size of each interior angle of a regular 15-sided polygon.
Answer: 156°
- Angle sum = (15 − 2) × 180° = 2,340°
- 2,340° ÷ 15 = 156°
3.Find the size of each exterior angle of a regular octagon.
Answer: 45°
- Exterior angles add to 360°
- 360° ÷ 8 = 45°
4.Each exterior angle of a regular polygon is 45°. How many sides does it have?
Answer: 8
- Exterior angles add to 360°
- 360 ÷ 45 = 8 sides
5.Find the sum of the interior angles of an octagon.
Answer: 1,080°
- Angle sum = (n − 2) × 180°
- (8 − 2) × 180° = 1,080°
6.Find the size of each interior angle of a regular hexagon.
Answer: 120°
- Angle sum = (6 − 2) × 180° = 720°
- 720° ÷ 6 = 120°
7.Find the size of each exterior angle of a regular 20-sided polygon.
Answer: 18°
- Exterior angles add to 360°
- 360° ÷ 20 = 18°
8.Each exterior angle of a regular polygon is 24°. How many sides does it have?
Answer: 15
- Exterior angles add to 360°
- 360 ÷ 24 = 15 sides
9.Find the sum of the interior angles of a 15-sided polygon.
Answer: 2,340°
- Angle sum = (n − 2) × 180°
- (15 − 2) × 180° = 2,340°
10.Find the size of each interior angle of a regular nonagon.
Answer: 140°
- Angle sum = (9 − 2) × 180° = 1,260°
- 1,260° ÷ 9 = 140°
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