Question

A circle has a circumference of 18.84 inches. What is the area of the circle?

A. 6 square inches
B. 18.84 square inches
C.28.26 square inches

Answer 1

Explanation:

28.26 because your looking for the areas radius,

formula: A =
`\pi r^(2)` ;

18.84/6.28

because C = 2 x pi x r (circumference, and were using 2 x 3.14)

so you get 3

3 is your radius in circumference formula and area

then we do 3 x 3 = 9 because you squaring the number for the areas formula. ( A =
`\pi r^(2)\\` )

so now you do 9 x 3.14 (pi) = 28.26.

Answer 2

C 28.26

Explanation:

Circumference is definded as:

`c=2\pi r~~~~(1)`

Area is definded as:

`A=\pi r^(2)~~~~(2)`

The unknown values are A and r, so we can solve (1) for r and replace it in (2)

`r=(c)/(\pi )~~~~~(3)`

we replace (3) in (2) and we get

`A=\pi ((c)/(\pi))^(2) =\pi (c^(2) )/(\pi^(2) )= (c^(2) )/(\pi )~~~~(4)`

c=18,84, so we have

`A=(18.84^(2) )/(\pi )=(354.9456)/(3.141582)\approx 28.26`