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Example Questions
Example Question #43 : Circles
The area of a circle is . Find the diameter.
The formula for the area of a circle is
with r being the length of the radius.
Since we know that the area of the circle is
we can solve for r and get 12. (Do so by canceling out the two pi's and taking the square root of 144). Once we know the radius, we can easily find the diameter, since the diameter is twice the length of the radius. Therefore, the diameter is 24, as
Example Question #11 : Diameter
Give the diameter of a circle with radius forty-two inches.
None of these
The diameter of a circle is twice its radius, so if a circle has radius 42 inches, its diameter is
Divide by 12 to convert to feet:
Example Question #1 : How To Find The Ratio Of Diameter And Circumference
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
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