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The five circles making up this archery target have diameters of length and. What is the total red area?

Simplify your answer as much as you can. You can use pi in your answer if necessary (for example, if the answer were, you could enter "3pi" or "3*pi" or "$3\pi$").

Apr 7, 2019

#1
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You didn't specify the diameters but.....if memory serves from answering this problem before....I believe that the diameters were 2, 4, 6, 8 and 10

So....the radiuses are 1, 2, 3, 4 and 5

The inner red area  is easy  =  pi (1)^2  =  1pi

The   next red area  =   area of 3rd circle - area of second circle  =  pi (3^2 - 2^2) = pi (9 - 4)  = 5pi

The outer red area is =   area of 5th circle - area of 4th circle  = pi (5^2 - 4^2) = pi (25 - 16) = 9pi

So....the total of the red areas  = [ 1 + 5 + 9 ]  =  15 pi   [units^2 ]

Apr 7, 2019
#2
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thanks!

donkey  Apr 13, 2019