+65 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 "$3\pi$").
+128475 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 ]
