What is the diameter of a circle whose area is #16##pi#?

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Answer 1 · 2015-12-25T02:39:28

#8#

Use the formula for the area of a circle:

#A=pir^2#

Here, the area is #16pi#:

#16pi=pir^2#

Divide both sides by #pi#:

#16=r^2#

Take the square root of both sides:

#sqrt16=sqrt(r^2)#

#4=r#

Since the radius of the circle is #4#, the diameter is twice that:

#d=4xx2=8#

Answer 2 · 2018-08-08T02:20:32

#8#

Recall the formula for the area of a circle:

#A=pir^2#, with radius #r#

We see that our radius is #sqrt16#, or #4#.

Recall that the diameter is twice the length of the radius, so we can multiply this by #2# to get a diameter of #8#.

Hope this helps!