SOLUTION: two circles have circumferences that add up to 12(pie) centimeters, and areas that add up to 20(pie) sqaure centimeters. Find the radius of each circle.
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Question 869347: two circles have circumferences that add up to 12(pie) centimeters, and areas that add up to 20(pie) sqaure centimeters. Find the radius of each circle. Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! two circles have circumferences that add up to 12(pie) centimeters, and areas that add up to 20(pie) square centimeters. Find the radius of each circle.
let x=radius of larger 1st circle
let y=radius of smaller 2nd circle
circumference of 1st circle=2πx
circumference of 1st circle=2πy
2πx+2πy=12π
x+y=6
y=6-x
..
area of 1st circle=πx^2
area of 2nd circle=πy^2=π(x-6)^2
πx^2+πy^2=20π
x^2+y^2=20
x^2+(6-x)^2=20
x^2+36-12x+x^2=20
2x^2-12x+16=0
x^2-6x+8=0
(x-4)(x-2)=0
x=4
or
x=2
radius of larger 1st circle=4 cm
radius of smaller 2nd circle=2 cm
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