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Which of the following is true for a circle that has an area of approximately 113 square feet?

a
The diameter is 6 feet and the circumference is 38 square feet.
b
The radius is 6 feet and the circumference is 38 square feet.
c
The diameter is 6 feet and the circumference is 38 feet.
d
The radius is 6 feet and the circumference is 38 feet.

1 Answer

5 votes

Answer:

radius is 6, diameter is 12, circumference is 38

Explanation:

The area of a circle hs the following formula:

A = π*r², where r is the circle radius (distance from center to edge of circle)

So, we have A = 113 = π*r²

Divide both sides by π: 113/π = r²

Approximately: 35.97 = r²

Square-root both sides: 5.997 = r

So, the radius is about 6 feet

The circumference of a circle has the following formula:

C = π * D, where D is the diameter of the circle (distance from one side of circle to opposite side, through the center)

But the length of a diameter is just that of two radiuses. (This is obvious when the 2 radii are collinear.)

Since r = 6 feet, D = 12 feet, and the circumference C = 12 * π = 37.699, about 38 feet.

*** So the radius is about 6 feet, the diameter is about 12 feet, and the circumference is about 38 feet,

It lloks like b and d are identical. Typo. maybe?

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