Find Circumference And Area Of A Circle

1. Find the circumference of a circle with a radius of 5 meters.

30 meters

40 meters

50 meters

60 meters

The circumference of a circle can be calculated using the formula C = 2πr, where r is the radius of the circle. In this case, the radius is given as 5 meters. Substituting this value into the formula, we get C = 2π(5) = 10π meters. Since the value of π is approximately 3.14, the circumference of the circle is approximately 10(3.14) = 31.4 meters. Therefore, the closest answer to the actual circumference is 30 meters.

Explanation

The circumference of a circle can be calculated using the formula C = 2πr, where r is the radius of the circle. In this case, the radius is given as 5 meters. Substituting this value into the formula, we get C = 2π(5) = 10π meters. Since the value of π is approximately 3.14, the circumference of the circle is approximately 10(3.14) = 31.4 meters. Therefore, the closest answer to the actual circumference is 30 meters.

2. Find the circumference of a circle with a radius of 12 inches.

72 meters

82 inches

72 inches

82 meters

The circumference of a circle is calculated using the formula C = 2πr, where r is the radius of the circle. In this case, the radius is given as 12 inches. Plugging this value into the formula, we get C = 2π(12) = 24π inches. Since the value of π is approximately 3.14, the circumference is approximately 24(3.14) = 75.36 inches. Therefore, the correct answer is 72 inches.

Explanation

The circumference of a circle is calculated using the formula C = 2πr, where r is the radius of the circle. In this case, the radius is given as 12 inches. Plugging this value into the formula, we get C = 2π(12) = 24π inches. Since the value of π is approximately 3.14, the circumference is approximately 24(3.14) = 75.36 inches. Therefore, the correct answer is 72 inches.

3. Find the circumference of a circle with a diameter of 25.

150

50

75

0

The circumference of a circle can be found by multiplying the diameter by pi (π). In this case, the diameter is given as 25. So, the circumference would be 25 * π. Since an approximate value of π is 3.14, the circumference would be approximately 78.5. However, the closest option to this value is 75, so that would be the correct answer.

Explanation

The circumference of a circle can be found by multiplying the diameter by pi (π). In this case, the diameter is given as 25. So, the circumference would be 25 * π. Since an approximate value of π is 3.14, the circumference would be approximately 78.5. However, the closest option to this value is 75, so that would be the correct answer.

4. A sprinkler can spray water 10 feet in all direction. How much area can the sprinkler water?

200 sq. feet

300 sq. feet

60 sq. feet

600 sq. feet

The sprinkler can spray water in all directions for a distance of 10 feet. This means that the sprinkler can cover a circular area with a radius of 10 feet. The formula to calculate the area of a circle is πr^2, where r is the radius. Therefore, the area covered by the sprinkler is approximately 3.14 * 10^2 = 314 square feet. However, since the options provided are in multiples of 100, the closest option is 300 square feet.

Explanation

The sprinkler can spray water in all directions for a distance of 10 feet. This means that the sprinkler can cover a circular area with a radius of 10 feet. The formula to calculate the area of a circle is πr^2, where r is the radius. Therefore, the area covered by the sprinkler is approximately 3.14 * 10^2 = 314 square feet. However, since the options provided are in multiples of 100, the closest option is 300 square feet.

5. Find the area of a circle with a diameter of 18 meters.

54 sq. meters

143 sq. meters

233 sq. meters

243 sq. meters

The area of a circle can be found using the formula A = πr^2, where r is the radius of the circle. Since the diameter is given as 18 meters, the radius is half of that, which is 9 meters. Plugging this value into the formula, we get A = π(9^2) = 81π. Approximating π to 3.14, we find that the area is approximately 254.34 square meters. Therefore, the closest answer is 243 square meters.

Explanation

The area of a circle can be found using the formula A = πr^2, where r is the radius of the circle. Since the diameter is given as 18 meters, the radius is half of that, which is 9 meters. Plugging this value into the formula, we get A = π(9^2) = 81π. Approximating π to 3.14, we find that the area is approximately 254.34 square meters. Therefore, the closest answer is 243 square meters.

6. What is the number of square meters of a half circle whose diameter is 8 meters?

56

48

12

24

The number of square meters of a half circle can be found by calculating the area of the corresponding full circle and then dividing it by 2. The formula for the area of a circle is A = πr^2, where r is the radius. In this case, the diameter is given as 8 meters, so the radius is 4 meters. Plugging this value into the formula, we get A = π(4^2) = 16π. Dividing this by 2, we get 8π. Since the value of π is approximately 3.14, the area of the half circle is approximately 8(3.14) = 25.12 square meters. The closest option to this value is 24, which is the correct answer.

Explanation

The number of square meters of a half circle can be found by calculating the area of the corresponding full circle and then dividing it by 2. The formula for the area of a circle is A = πr^2, where r is the radius. In this case, the diameter is given as 8 meters, so the radius is 4 meters. Plugging this value into the formula, we get A = π(4^2) = 16π. Dividing this by 2, we get 8π. Since the value of π is approximately 3.14, the area of the half circle is approximately 8(3.14) = 25.12 square meters. The closest option to this value is 24, which is the correct answer.