SOLUTION: Find the diameter of the circle that has a circumference equal to its area. 2 4 8 10

Algebra ->  Surface-area -> SOLUTION: Find the diameter of the circle that has a circumference equal to its area. 2 4 8 10       Log On


   

Question 818618: Find the diameter of the circle that has a circumference equal to its area.
2
4
8
10
Answer by jhunjiro(67) About Me  (Show Source):
You can put this solution on YOUR website!
Solution:
Area of circle = %28pi%29r%5E2 or %28pi%29D%5E2%2F4
Perimeter = 2%28pi%29r or %28pi%29D
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%28pi%29D%5E2%2F4 = %28pi%29D
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%284%2Fpi%29%2A%28%28pi%29D%5E2%2F4%29=%28pi%29D%2A%284%2Fpi%29
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D%5E2=4D
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D%5E2-4D=0
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D%28D-4%29=0
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D-4=0
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D=4
Final Answer :
D=4