Year 7 Angles in Polygons Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 7 angles worksheet.
Success TutoringWorksheetsAnswer sheetYear 7 · Mathematics · AnglesYear 7 Angles in Polygons Worksheet — Level 2 — 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 a dodecagon.
Answer: 1,800°
- Angle sum = (n − 2) × 180°
- (12 − 2) × 180° = 1,800°
2.Find the size of each interior angle of a regular dodecagon.
Answer: 150°
- Angle sum = (12 − 2) × 180° = 1,800°
- 1,800° ÷ 12 = 150°
3.Find the size of each exterior angle of a regular decagon.
Answer: 36°
- Exterior angles add to 360°
- 360° ÷ 10 = 36°
4.Each exterior angle of a regular polygon is 36°. How many sides does it have?
Answer: 10
- Exterior angles add to 360°
- 360 ÷ 36 = 10 sides
5.Find the sum of the interior angles of a pentagon.
Answer: 540°
- Angle sum = (n − 2) × 180°
- (5 − 2) × 180° = 540°
6.Find the size of each interior angle of a regular nonagon.
Answer: 140°
- Angle sum = (9 − 2) × 180° = 1,260°
- 1,260° ÷ 9 = 140°
7.Find the size of each exterior angle of a regular dodecagon.
Answer: 30°
- Exterior angles add to 360°
- 360° ÷ 12 = 30°
8.Each exterior angle of a regular polygon is 72°. How many sides does it have?
Answer: 5
- Exterior angles add to 360°
- 360 ÷ 72 = 5 sides
9.Find the sum of the interior angles of a 11-sided polygon.
Answer: 1,620°
- Angle sum = (n − 2) × 180°
- (11 − 2) × 180° = 1,620°
10.Find the size of each interior angle of a regular 18-sided polygon.
Answer: 160°
- Angle sum = (18 − 2) × 180° = 2,880°
- 2,880° ÷ 18 = 160°
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