Circles 7

A bicycle wheel has a radius of 14.25 inches. What is the approximate circumference of the wheel?

• 22 inches

• 45 inches

• 54 inches

• 89 inches

Answer explanation

The circumference of a circle is calculated using the formula 2 * π * radius. Substituting the given radius of 14.25 inches, the approximate circumference is 2 * 3.14 * 14.25 = 89 inches.

Find the circumference of the circle rounded to the nearest whole number.

• 30 in.

• 15 in.

• 31 in.

• 75 in.

Answer explanation

The correct answer is 31 in. To find the circumference of a circle, you use the formula: Circumference = 2 * π * radius. Given the radius, you can calculate the circumference, which in this case rounds to 31 inches.

Find the area of the circle.

• 21.98 cm²

• 38.47 cm²

• 43.96 cm²

• 153.86 cm²

Answer explanation

To find the area of a circle, use the formula A = πr^2. Given the radius, calculate A = π(3.5)^2 = 38.47 cm^2. Therefore, the correct answer is 38.47 cm^2.

Find the area of a circle in feet with the radius being 3'.

• 18.84 sq. ft.

• 28.26 sq. ft

• 88.73 sq. ft

• 90 sq.ft

Answer explanation

To find the area of a circle, use the formula A = πr^2. Substituting r = 3', A = π(3)^2 = 28.26 sq. ft. Therefore, the correct answer is 28.26 sq. ft.

The area of a circle is 153.86 m². What is the radius?

• 7

• 14

• 28

• 49

Answer explanation

To find the radius of a circle from its area, use the formula A = πr^2. Given A = 153.86, solve for r: r = √(A/π) = √(153.86/π) ≈ 7. Therefore, the radius is 7.

The center circle of a baskeball court has a diameter of 12 feet. What is the area of the circle?

• 18.84 ft²

• 37.68 ft²

• 452.16 ft²

• 113.04 ft²

Answer explanation

The area of a circle is calculated using the formula A = πr^2. Given the diameter is 12 feet, the radius is half of that, which is 6 feet. Substituting the values, A = π(6)^2 = 113.04 ft^2.

Stacey is putting a border around a circular flowerbed. The diameter of the flowerbed is 5 feet. What is the circumference, in feet?

• 78.5 ft.

• 15.7 ft.

• 19.6 ft.

• 7.9 ft.

Answer explanation

The circumference of a circle is calculated using the formula C = πd, where d is the diameter. Substituting d = 5 feet, C = π*5 = 15.7 ft. Therefore, the correct answer is 15.7 ft.

If a circular pond has a diameter of 10 meters, what is its area?

• 78.5 m²

• 31.4 m²

• 157 m²

• 314 m²

A round table cover has a radius of 2 feet. Calculate the circumference of the table cover.

• 4 ft

• 6 ft

• 12.56 ft

• 25.12 ft

What is the radius of a circle whose circumference is approximately 62.8 meters?

• 10 m

• 20 m

• 5 m

• 15 m