Question 1: Calculate the radius of a circle with a diameter of 14 cm.

Answer: 7

Question 2: A circle has a radius of 9 meters. Find its circumference. (Use π ≈ 3.14)

Answer: 56.52

Question 3: If the radius of a circle is doubled, describe how the circumference changes. Explain your reasoning.

Answer: The circumference doubles because circumference = 2πr, so when r doubles, circumference doubles.

Question 4: Construct a circle with a radius of 5 cm and draw its diameter.

Answer: 10 cm

Question 5: A circular garden has a radius of 12 meters. A path of width 2 meters is built around it. What is the new radius of the outer edge of the path?

Answer: 14

Question 6: A wheel has a radius of 0.5 meters. How many rotations does it make to cover a distance of 31.4 meters? (Use π ≈ 3.14)

Answer: 100

Question 7: Identify and correct the mistake: A student claims that the radius of a circle is equal to its diameter divided by 2. True or false? Justify your answer.

Answer: True. Because radius = diameter / 2.

Question 8: Calculate the area of a circle with radius 8 cm. (Use π ≈ 3.14)

Answer: 201.06

Question 9: A circular pond has a radius of 10 meters. A rectangular fence surrounds it, with length twice the radius and width three times the radius. Calculate the total length of the fence.

Answer: 80 meters

Question 10: A student sees two circles: one with radius 3 cm and another with radius 6 cm. Which circle has a larger circumference, and by what factor?

Answer: The circle with radius 6 cm has a larger circumference, exactly twice that of the 3 cm radius circle.

Question 11: Error Analysis: A student computes the radius of a circle with diameter 20 cm as 10 cm, but then mistakenly calculates its area using πr² with r=10 cm. Is their area calculation correct? Explain why or why not.

Answer: Yes, the area calculation is correct because radius is half of diameter, so r=10 cm, and area = π×10² = 314.