Grade 8 Surface Area & Volume worksheet
from Gradelings · Name: ______________________
How to explain it
- Surface area is the area of all the faces added up.
- Volume of a cylinder: V = π × r² × h.
- Use π ≈ 3.14.
Example: A cylinder has radius 3 cm and height 5 cm. What is its volume? r² = 3 × 3 = 9. V ≈ 3.14 × 9 × 5 = 141.3. Answer: About 141.3 cm³
Question 1
A box is 2 cm long, 10 cm wide and 10 cm tall. What is its surface area?
answer boxcm²
280 cm²
Hint: Add the areas of the 3 pairs of faces: 2 × (2×10 + 2×10 + 10×10) = 2 × 140 = 280 cm².
Question 2
A cube has edges of 9 cm. What is its surface area?
answer boxcm²
486 cm²
Hint: A cube has 6 identical square faces: 6 × 9² = 6 × 81 = 486 cm².
Question 3
A triangular prism has a triangle base of 20 cm and height 7 cm. The prism is 12 cm long. What is its volume?
answer boxcm³
840 cm³
Hint: Area of the triangle = ½ × 20 × 7 = 70 cm². Volume = base area × length = 70 × 12 = 840 cm³.
Question 4
A cylinder has a radius of 8 cm and a height of 16 cm. What is its volume? Use π ≈ 3.14 and round to 1 decimal place.
answer boxcm³
3215.4 cm³
Hint: V = π × r² × h ≈ 3.14 × 64 × 16 = 3215.36. Rounded: 3215.4 cm³.
Question 5
What is the surface area of a closed cylinder with radius 8 cm and height 20 cm? Use π ≈ 3.14 and round to 1 decimal place.
answer boxcm²
1406.7 cm²
Hint: SA = 2πr² + 2πrh = 2π × 8 × (8 + 20) ≈ 3.14 × 448 = 1406.72. Rounded: 1406.7 cm².
Question 6
A box with a volume of 12 cm³ is 3 cm long and 2 cm wide. How tall is it?
answer boxcm
2 cm
Hint: Volume = l × w × h, so h = 12 ÷ (3 × 2) = 12 ÷ 6 = 2 cm.
Question 7
A fish tank holds 4500 cm³ of water. How many millilitres is that?
answer boxmL
4500 mL
Hint: 1 cm³ holds exactly 1 mL, so the number stays the same.
Question 8
Looking straight down at the top of a cylinder, which shape do you see?
- a circle
- a triangle
- an oval with no edge
- a rectangle
a circle
Hint: The top face of a cylinder is a circle. The side view is a rectangle.
Question 9
A box is 2 cm long, 3 cm wide and 6 cm tall. What is its surface area?
answer boxcm²
72 cm²
Hint: Add the areas of the 3 pairs of faces: 2 × (2×3 + 2×6 + 3×6) = 2 × 36 = 72 cm².
Question 10
A cube has edges of 4 cm. What is its surface area?
answer boxcm²
96 cm²
Hint: A cube has 6 identical square faces: 6 × 4² = 6 × 16 = 96 cm².
Answer key
- 1. 280 cm²
- 2. 486 cm²
- 3. 840 cm³
- 4. 3215.4 cm³
- 5. 1406.7 cm²
- 6. 2 cm
- 7. 4500 mL
- 8. a circle
- 9. 72 cm²
- 10. 96 cm²
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