SOLUTION: find the length of a radius of a circle whose area and circumference are the same non zero number

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Question 650021: find the length of a radius of a circle whose area and circumference are the same non zero number
Found 2 solutions by swincher4391, MathLover1:
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
Find r such that pir^2 = 2pir
pi+%2A+r%5E2+=+2%2Api%2Ar
Divide both sides by pi
r%5E2+=+2r
r%5E2-2r+=+0
r%28r-2%29+=+0
r= 0 or r=2
r=2 is the only non-zero number that fits the bill.
2.

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!


A=r%5E2%2Api
c=2r%2Api
if area and circumference are the same non zero number, then
r%5E2%2Api=2r%2Api
r%5Ecross%282%29%2Across%28pi%29=2cross%28r%29%2Across%28pi%29
r=2
check:
A=r%5E2%2Api...=>...A=2%5E2%2Api=4pi
c=2r%2Api..=>...c=2%2A2%2Api=4pi