Year 5 Angles Worksheet — Level 3 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 5 angles worksheet.
Success TutoringWorksheetsAnswer sheetYear 5 · Mathematics · AnglesYear 5 Angles Worksheet — Level 3 — Practice Set 3 — Answers
State the angle rule you use.
1.Two angles on a straight line are 135° and x°. Find x.
Answer: x = 45
- Angles on a straight line add to 180°
- x = 180 − 135 = 45
2.Two angles of a triangle are 80° and 58°. Find the third angle.
Answer: 42°
- Angles in a triangle add to 180°
- 180 − 80 − 58 = 42
3.Three angles meet at a point: 108°, 59° and x°. Find x.
Answer: x = 193
- Angles at a point add to 360°
- x = 360 − 108 − 59 = 193
4.Two angles of a triangle are 36° and 66°. Find the third angle.
Answer: 78°
- Angles in a triangle add to 180°
- 180 − 36 − 66 = 78
5.Two angles on a straight line are 86° and x°. Find x.
Answer: x = 94
- Angles on a straight line add to 180°
- x = 180 − 86 = 94
6.Two angles on a straight line are 90° and x°. Find x.
Answer: x = 90
- Angles on a straight line add to 180°
- x = 180 − 90 = 90
7.Two angles on a straight line are 132° and x°. Find x.
Answer: x = 48
- Angles on a straight line add to 180°
- x = 180 − 132 = 48
8.Three angles meet at a point: 54°, 84° and x°. Find x.
Answer: x = 222
- Angles at a point add to 360°
- x = 360 − 54 − 84 = 222
9.An isosceles triangle has an apex angle of 20°. Find each base angle.
Answer: 80°
- Base angles are equal: (180 − 20) ÷ 2
- = 160 ÷ 2 = 80
10.An isosceles triangle has an apex angle of 75°. Find each base angle.
Answer: 52.5°
- Base angles are equal: (180 − 75) ÷ 2
- = 105 ÷ 2 = 52.5
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.