Question

Please help me :)))))

Answer 1

Part a)

Answer: 5*sqrt(2pi)/pi

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Work Shown:

r = sqrt(A/pi)
r = sqrt(50/pi)
r = sqrt(50)/sqrt(pi)
r = (sqrt(50)*sqrt(pi))/(sqrt(pi)*sqrt(pi))
r = sqrt(50pi)/pi
r = sqrt(25*2pi)/pi
r = sqrt(25)*sqrt(2pi)/pi
r = 5*sqrt(2pi)/pi

Note: the denominator is technically not able to be rationalized because of the pi there. There is no value we can multiply pi by so that we end up with a rational value. We could try 1/pi, but that will eventually lead back to having pi in the denominator. I think your teacher may have made a typo when s/he wrote "rationalize all denominators"

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Part b)

Answer: 3*sqrt(3pi)/pi

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Work Shown:

r = sqrt(A/pi)
r = sqrt(27/pi)
r = sqrt(27)/sqrt(pi)
r = (sqrt(27)*sqrt(pi))/(sqrt(pi)*sqrt(pi))
r = sqrt(27pi)/pi
r = sqrt(9*3pi)/pi
r = sqrt(9)*sqrt(3pi)/pi
r = 3*sqrt(3pi)/pi

Note: the same issue comes up as before in part a)

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Part c)

Answer: sqrt(19pi)/pi

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Work Shown:

r = sqrt(A/pi)
r = sqrt(19/pi)
r = sqrt(19)/sqrt(pi)
r = (sqrt(19)*sqrt(pi))/(sqrt(pi)*sqrt(pi))
r = sqrt(19pi)/pi

Answer 2

Comment
The radius can be found by taking the square root of A divided by pi  under the root sign. 

Formula
r = sqrt(A / pi) 
r = sqrt(A * pi/( pi * p)i) 
the root of pi^2 is pi
r = sqrt(A * pi)/pi

Problem A
r = √(50 * π) / π <<<< answer 

Comment
For each problem, all you need do is put in the given areas in A B C. I don't know what your input will do with the square root sign; you can write sqrt(50 * pi) / pi

B
r = √(27*π) / π

C
r = √(19* π) / π