Year 8 Angles in Polygons Worksheet — Level 2 — Practice Set 3 — 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 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 an octagon.
Answer: 1,080°
- Angle sum = (n − 2) × 180°
- (8 − 2) × 180° = 1,080°
2.Find the size of each interior angle of a regular 36-sided polygon.
Answer: 170°
- Angle sum = (36 − 2) × 180° = 6,120°
- 6,120° ÷ 36 = 170°
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 60°. How many sides does it have?
Answer: 6
- Exterior angles add to 360°
- 360 ÷ 60 = 6 sides
5.Find the sum of the interior angles of a dodecagon.
Answer: 1,800°
- Angle sum = (n − 2) × 180°
- (12 − 2) × 180° = 1,800°
6.Find the size of each interior angle of a regular 24-sided polygon.
Answer: 165°
- Angle sum = (24 − 2) × 180° = 3,960°
- 3,960° ÷ 24 = 165°
7.Find the size of each exterior angle of a regular quadrilateral.
Answer: 90°
- Exterior angles add to 360°
- 360° ÷ 4 = 90°
8.Each exterior angle of a regular polygon is 18°. How many sides does it have?
Answer: 20
- Exterior angles add to 360°
- 360 ÷ 18 = 20 sides
9.Find the sum of the interior angles of a nonagon.
Answer: 1,260°
- Angle sum = (n − 2) × 180°
- (9 − 2) × 180° = 1,260°
10.Find the size of each interior angle of a regular pentagon.
Answer: 108°
- Angle sum = (5 − 2) × 180° = 540°
- 540° ÷ 5 = 108°
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