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Primary 3 Maths: Perimeter and Length — Practice Paper 3 (10 Questions)
Primary 3 Maths: Perimeter and Length — Practice Paper 3 (10 Questions)
Paper 3 moves the perimeter idea onto other shapes: an equilateral triangle, an isosceles triangle and a five-sided figure are all just one lap round the edge. A photo frame and a rebent wire show that the perimeter can stay the same while the shape changes.
Quick answer 10 questions, about 20 minutes. Items 01 to 03 cover a rectangle, a square and metres to centimetres; items 04 to 06 cover a larger rectangle, an equilateral triangle and the equal sides of an isosceles triangle; items 07 to 09 cover a pentagon, ribbon round a frame and a wire rebent from a square into a rectangle; item 10 redoes the single length-plus-width slip.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | 20 minutes |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: Primary 3 Maths: Perimeter and Length — Tutor Lesson Plan |
| Level | Primary 3 |
02 Questions (10 items)
- FoundationA rectangle is 12 cm long and 4 cm wide. What is its perimeter?
- FoundationA square has sides of 7 cm. What is its perimeter?
- FoundationConvert: (a) 1 m 60 cm into cm; (b) 520 cm into m and cm.
- IntermediateA rectangle is 30 cm by 18 cm. What is its perimeter?
- IntermediateAn equilateral triangle has sides of 14 cm. What is its perimeter?
- IntermediateAn isosceles triangle has a perimeter of 30 cm and a base of 8 cm. How long is each of the two equal sides?
- ChallengeA five-sided shape has sides of 6 cm, 8 cm, 5 cm, 9 cm and 12 cm. What is its perimeter?
- ChallengeA rectangular photo frame is 45 cm by 30 cm. Is a 200 cm ribbon long enough to go right round the edge, and how much is left?
- ChallengeA piece of wire is bent into a square of side 12 cm, then rebent into a rectangle 16 cm long. What is its width?
- Error redoFor a rectangle 20 cm by 5 cm a student answers a perimeter of 25 cm. What went wrong, and what is the right answer?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 32 cm | (12 + 4) × 2 = 32, and 12 + 4 + 12 + 4 = 32 checks it: two lengths plus two widths give the same total. |
| 2 | 28 cm | All four sides of a square are equal: 7 × 4 = 28 cm. Multiplying by 2 would count only two sides. |
| 3 | (a) 160 cm; (b) 5 m 20 cm | 1 m = 100 cm, so 1 m 60 cm = 100 + 60 = 160 cm. In 520 cm there are five lots of 100 cm with 20 cm left over. |
| 4 | 96 cm | 30 + 18 = 48 is one length plus one width, and 48 × 2 = 96. With larger numbers, add first and then double to avoid four separate additions. |
| 5 | 42 cm | An equilateral triangle has three equal sides, so 14 × 3 = 42 cm; a triangle is multiplied by 3, not by 4. |
| 6 | Each equal side is 11 cm | Take the base away first: 30 − 8 = 22 for the two equal sides together, then halve it to get 11. The check is 11 + 11 + 8 = 30. |
| 7 | 40 cm | There is no rectangle formula here, so walk the boundary and add each side: 6 + 8 + 5 + 9 + 12 = 40 cm. Write each length on the diagram before adding. |
| 8 | Yes, 50 cm left over (the frame needs 150 cm) | One lap of the frame is (45 + 30) × 2 = 150 cm, and 200 − 150 = 50 cm is left. A ribbon is long enough when it exceeds the perimeter. |
| 9 | 8 cm | The wire keeps its length: 12 × 4 = 48 cm is the perimeter, 48 ÷ 2 = 24 is one length plus one width, and 24 − 16 = 8. The check is 2 × (16 + 8) = 48. |
| 10 | Only one length and one width were added; the perimeter is 50 cm | 25 is just 20 + 5, one length plus one width. A rectangle has two of each, so double it: 25 × 2 = 50 cm. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
