Area of target board(circular shape) I know how to find area and circumference of target boards, but I dont know why I am finding one question from new mastering mathematics for Eexcel GCSE syllabus bit weird. As the answer scheme is published by publishers and work out of this question does not match anywhere near to it. I just want to get confirm if I am doing it write. 
So here is the question.

When I solve it I get answer 163.35 cm(square) for red area and 157.06 cm(square) for blue area and the difference would be 376.99cm(square). 
According to answer scheme the answer is 816.81 cm(square) for red area and 439.82 cm(square) for blue area and the difference would be 6.29.
 A: How to solve the question:
The first blue area is calculated using πr²
The first red area is calculated using πr² and then subtracting (the area of the first blue area)
The second blue area is calculated using πr² and then subtracting (the area of the first blue area + the area of the first red area)
The second red area is calculated using πr² and then subtracting (the area of the first blue area + the area of the first red area + the second blue area)
Total blue area = first blue area + second blue area
Total red area = first red area + second red area
Difference = total blue area - total red area
Working out:

First Blue Area: π(5)² = 25π 
First Red Area: π(9)² - (25π) = 81π - (25π) = 56π
Second Blue Area: π(14)² - (25π+56π) = 196π - (25π+56π) = 115π
Second Red Area: π(20)² - (25π+56π+115π) = 400π - (25π+56π+115π) = 204π
Total Red Area = 204π + 56π = 260π = 816.814089933 cm²
Total Blue Area = 25π + 115π = 140π = 439.822971503 cm² 
Difference between Total Red Area and Total Blue Area=
816.814089933 cm² - 439.822971503 cm² = 376.99111843 cm²

Let me know if you don't understand or need more help.
