Question

Rearrange the formula to calculate the diameter of a circle.

Answer 1

a=1/4pid^2
4a=pid^2
4a/pi=d^2
square both sides to get d
Answer: Square root of 4a over pi equals d.

Answer 2

To find your answer, you want to get everything but the variable "d," the diameter, onto one side of the equal sign, leaving d by itself.

1) Start by multiplying both sides by 4 to get rid of the 4 in the denominator on the right. bringing it to the other side:
$A = \frac{1}{4} \pi d^{2} \\ 4(A) = 4(\frac{1}{4} \pi d^{2} )\\ 4A = \pi d^{2}$

2) Divide both sides by π to move the π to the other side of the equation (I put the d squared on the left, but you can keep it on the right):
$4A = \pi d^{2} \\ d^{2} = \frac{4A}{ \pi }$

3) Finally, take the square root of both sides to get the value of d:
$d^{2} = \frac{4A}{ \pi } \\ d = \sqrt{\frac{4A}{ \pi } }$

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Answer: $d = \sqrt{\frac{4A}{ \pi } }$