how do you find the surface area of a sphere if the circonference measures 20 pie ft?
A. 1256.6ft squared
B. 10ft squared
C. 314.2ft squared
D. 62.8ft squared
D.62.8ft squared
To find the surface area of a sphere, you need to use the formula:
Surface Area = 4πr²
In this case, we are given the circumference of the sphere as 20π ft. The formula for circumference is:
Circumference = 2πr
To find the radius (r), we can rearrange the circumference formula:
r = Circumference / (2π)
Plugging in the given circumference:
r = (20π ft) / (2π) = 10 ft
Now that we have the radius, we can use the surface area formula:
Surface Area = 4π(10 ft)² = 400π ft²
To simplify the answer, let's use an approximation for the value of π:
Surface Area ≈ 400 × 3.14 ft² ≈ 1256.6 ft²
Therefore, the correct answer is A. 1256.6ft².