Add all the numbers in the ratio together to get 18 then divide 180 by 18 to equal 10. then times that by each individual number in the ratio. so the answer is 40:50:90
let's find the area of the outer circle and the inside circle
the inside's circle area
A= π x 6²=36π
the outer's
A' = π x 4x²= 4πx²
A'-A=4πx²- 36π=160πcm² equivalent to x²- 9=40, so x²=49 implies x =sqrt(49)=7, x=7.
You could do 37+230 or 40 + 235
