Let's solve each problem step by step using the formulas for
area and
perimeter of different shapes.
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🔷 Formulas:
-
Rectangle:
- Area = length × width
- Perimeter = 2 × (length + width)
-
Square:
- Area = side × side (or $ s^2 $)
- Perimeter = 4 × side
-
Triangle:
- Area = $ \frac{1}{2} \times \text{base} \times \text{height} $
- Perimeter = sum of all three sides *(Note: Only base and height are given in some cases, so we assume only area is required unless all sides are known)*
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Now let’s go through each question:
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1. Rectangle: 10m × 4m
-
Area = length × width = $ 10 \times 4 = 40 \, \text{m}^2 $
-
Perimeter = $ 2 \times (10 + 4) = 2 \times 14 = 28 \, \text{m} $
✔ Answer:
Area =
40 m², Perimeter =
28 m
---
2. Triangle: Base = 9m, Height = 6m
-
Area = $ \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 9 \times 6 = 27 \, \text{m}^2 $
⚠️ We don't have the lengths of the other two sides, so
perimeter cannot be calculated with given info.
✔ Answer:
Area =
27 m², Perimeter =
Not enough info
---
3. Square: Side = 7m
-
Area = $ 7 \times 7 = 49 \, \text{m}^2 $
-
Perimeter = $ 4 \times 7 = 28 \, \text{m} $
✔ Answer:
Area =
49 m², Perimeter =
28 m
---
4. Triangle: Base = 8m, Height = 12m
-
Area = $ \frac{1}{2} \times 8 \times 12 = 4 \times 12 = 48 \, \text{m}^2 $
⚠️ Again, only base and height are given. No side lengths →
perimeter not possible.
✔ Answer:
Area =
48 m², Perimeter =
Not enough info
---
5. Rectangle: 20m × 7m
-
Area = $ 20 \times 7 = 140 \, \text{m}^2 $
-
Perimeter = $ 2 \times (20 + 7) = 2 \times 27 = 54 \, \text{m} $
✔ Answer:
Area =
140 m², Perimeter =
54 m
---
6. Rectangle: 11m × 8m
-
Area = $ 11 \times 8 = 88 \, \text{m}^2 $
-
Perimeter = $ 2 \times (11 + 8) = 2 \times 19 = 38 \, \text{m} $
✔ Answer:
Area =
88 m², Perimeter =
38 m
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✔ Final Answers Summary:
| Problem | Shape | Area | Perimeter |
|--------|--------------|------------|---------------|
| 1 | Rectangle | 40 m² | 28 m |
| 2 | Triangle | 27 m² | Not enough info |
| 3 | Square | 49 m² | 28 m |
| 4 | Triangle | 48 m² | Not enough info |
| 5 | Rectangle | 140 m² | 54 m |
| 6 | Rectangle | 88 m² | 38 m |
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💡
Note: For triangles #2 and #4, only base and height are provided, so we can compute
area, but
perimeter requires knowing all three side lengths — which aren’t given. So those perimeters are
not solvable with current information.
Let me know if you'd like to estimate perimeter assuming it's an isosceles triangle!
Parent Tip: Review the logic above to help your child master the concept of find the area worksheet.