Question

Multiple Choice Please help!!

1. Find the surface area for a sphere with a radius of 10 feet. Round to the nearest whole number.
1,256 ft2
4,189 ft2
1,089 ft2
1,568 ft2

Answer 1

Answer: Choice A) 1,256 ft^2

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Work Shown:

`\text{SA} =\text{Surface area of a sphere of radius r}\\\\\text{SA} = 4\pi*r^2\\\\\text{SA} = 4\pi*10^2\\\\\text{SA} = 400\pi\\\\\text{SA} \approx 400(3.14)\\\\\text{SA} \approx 1256 \ \text{square feet}\\\\`

The above steps apply when we use the approximation pi = 3.14

If you use more decimal digits of pi from your calculator, then,

`\text{SA} = 400\pi\\\\\text{SA} \approx 400(3.1415926535898)\\\\\text{SA} \approx 1256.63706143591\\\\\text{SA} \approx 1257\\\\`

which isn't too far off from the 1256 calculated earlier.