Question 1: State the formula for calculating the surface area of a sphere with radius r.

Answer: Surface area = 4πr²

Question 2: Calculate the surface area of a sphere with radius 5 cm. (Use π ≈ 3.14)

Answer: 314 cm²

Question 3: Write the formula for the volume of a sphere in terms of radius r.

Answer: Volume = (4/3)πr³

Question 4: Determine the volume of a sphere with radius 7 m. (Use π ≈ 3.14)

Answer: 1436.76 m³

Question 5: A spherical ball has a diameter of 12 cm. Calculate its surface area.

Answer: 452.16 cm²

Question 6: If the surface area of a sphere is 500 cm², find its radius. (Use π ≈ 3.14)

Answer: ≈ 6.3 cm

Question 7: A spherical water tank has a volume of 1500 m³. What is its radius? (Use π ≈ 3.14)

Answer: ≈ 9.3 m

Question 8: Construct a sphere on the grid with a radius of 3 units. Use the grid to illustrate.

Answer: Student's diagram

Question 9: A spherical globe is 20 cm in diameter. Calculate its surface area and volume, showing all steps.

Answer: Surface area ≈ 1256 cm², Volume ≈ 4189 cm³

Question 10: Identify and correct the mistake in the following student calculation: The surface area of a sphere with radius 4 cm is given as 64π cm².

Answer: Incorrect formula used; Surface area = 4πr² = 4π(4)² = 4π(16) = 64π, not just 64π cm².

Question 11: A student claims that doubling the radius of a sphere doubles its surface area. Is this statement true or false? Justify your answer.

Answer: False; surface area = 4πr², so doubling r increases surface area by a factor of four.