Question 1: Calculate the area of a circle with a radius of 3 cm. (Use π ≈ 3.14)

Answer: 28.26

Question 2: A circle has an area of 50 cm². Find its radius, using π ≈ 3.14.

Answer: 3.99

Question 3: Construct a circle with an area of approximately 78.5 cm². What should be its radius?

Answer: 5

Question 4: Identify the mistake in the following calculation: A circle with radius 4 cm has an area calculated as 16π cm².

Answer: Incorrect; the area should be π×4²=16π, which is correct. But if they used 16 as the radius squared, their area is correct; the mistake could be misreading the formula or substituting incorrectly.

Question 5: A garden is circular with a radius of 6 meters. What is the area of the garden? (Use π ≈ 3.14)

Answer: 113.04

Question 6: If the radius of a circle increases from 4 cm to 6 cm, by what factor does its area increase?

Answer: 2.25

Question 7: A circular pool has an area of 78.5 m². What is its radius? (Use π ≈ 3.14)

Answer: 5

Question 8: Plot the graph of y = 2πr for radius values from 1 to 5. (Use the grid to draw)

Answer: Students draw the graph

Question 9: A picture frame is circular with a radius of 8 cm. What is the area of the frame? (Use π ≈ 3.14)

Answer: 201.06

Question 10: Challenge: The radius of a circle is doubled. How does the area change? Explain your reasoning.

Answer: The area increases by a factor of 4 because area is proportional to radius squared.

Question 11: An error was made in calculating the area of a circle with radius 5 cm as 50π cm². Identify and correct the mistake.

Answer: Incorrect; the correct area should be 25π cm², since A=πr² and 5²=25.