Let's solve each polygon step by step, calculating both
area and
perimeter, and writing the
number model (formula and calculation) for each.
---
1. Rectangle: 15 in × 3 in
-
Area:
Formula: $ \text{Area} = \text{length} \times \text{width} $
$ 15 \times 3 = 45 $
→
Area = 45 square inches
-
Perimeter:
Formula: $ \text{Perimeter} = 2(\text{length} + \text{width}) $
$ 2(15 + 3) = 2(18) = 36 $
→
Perimeter = 36 inches
✔ Answer:
- Area =
45 in²
- Perimeter =
36 in
---
2. Right Triangle: 6 cm, 10 cm, 11.7 cm
This is a right triangle with legs 6 cm and 10 cm, hypotenuse 11.7 cm.
-
Area:
Formula: $ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} $
Use the two legs as base and height:
$ \frac{1}{2} \times 6 \times 10 = 30 $
→
Area = 30 cm²
-
Perimeter:
Add all sides:
$ 6 + 10 + 11.7 = 27.7 $
→
Perimeter = 27.7 cm
✔ Answer:
- Area =
30 cm²
- Perimeter =
27.7 cm
---
3. Rectangle: 4 ft × 5 ft
-
Area:
$ 4 \times 5 = 20 $
→
Area = 20 ft²
-
Perimeter:
$ 2(4 + 5) = 2(9) = 18 $
→
Perimeter = 18 ft
✔ Answer:
- Area =
20 ft²
- Perimeter =
18 ft
---
4. Triangle: 5 m, 3 m, 6 m, height = 2 m
Base = 6 m, height = 2 m
-
Area:
$ \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 6 \times 2 = 6 $
→
Area = 6 m²
-
Perimeter:
Add all three sides:
$ 5 + 3 + 6 = 14 $
→
Perimeter = 14 m
✔ Answer:
- Area =
6 m²
- Perimeter =
14 m
---
5. Parallelogram: base = 9 cm, height = 2 cm, side = 3 cm
Note: The slanted side is 3 cm, and the base is 9 cm. Height is 2 cm.
-
Area:
Formula: $ \text{Area} = \text{base} \times \text{height} $
$ 9 \times 2 = 18 $
→
Area = 18 cm²
-
Perimeter:
Opposite sides are equal. So two sides of 9 cm and two of 3 cm:
$ 2(9 + 3) = 2(12) = 24 $
→
Perimeter = 24 cm
✔ Answer:
- Area =
18 cm²
- Perimeter =
24 cm
---
6. Rhombus: all sides = 3 m, height = 3 m
All four sides are 3 m (since it's a rhombus), and height is 3 m.
-
Area:
Formula: $ \text{Area} = \text{base} \times \text{height} $
$ 3 \times 3 = 9 $
→
Area = 9 m²
-
Perimeter:
All sides equal: $ 4 \times 3 = 12 $
→
Perimeter = 12 m
✔ Answer:
- Area =
9 m²
- Perimeter =
12 m
---
✔ Final Answers Summary:
| Shape | Area | Perimeter |
|------|------|-----------|
| 1. Rectangle (15×3 in) | 45 in² | 36 in |
| 2. Right Triangle (6,10,11.7 cm) | 30 cm² | 27.7 cm |
| 3. Rectangle (4×5 ft) | 20 ft² | 18 ft |
| 4. Triangle (5,3,6 m, h=2) | 6 m² | 14 m |
| 5. Parallelogram (9,3, h=2 cm) | 18 cm² | 24 cm |
| 6. Rhombus (side=3 m, h=3 m) | 9 m² | 12 m |
---
📝 Number Models (How to Show Work):
For example:
1.
Rectangle (15×3)
- Area: $ 15 \times 3 = 45 $
- Perimeter: $ 2(15 + 3) = 2(18) = 36 $
2.
Right Triangle
- Area: $ \frac{1}{2} \times 6 \times 10 = 30 $
- Perimeter: $ 6 + 10 + 11.7 = 27.7 $
And so on...
Let me know if you'd like this formatted into a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of perimeter of shapes worksheet.