Question 872322
The big circle has an area of pi*R^2


The small circles have individual areas of pi*r^2 and there are 4 of them, so they total to 4*pi*r^2


(Area of Big circle) - (Area of little circles) = Resulting area


pi*R^2 - 4*pi*r^2 = 8


you can optionally factor out pi to get


pi*(R^2 - 4r^2) = 8


and then factor the remaining bit using the difference of squares rule to get


pi*(R - 2r)*(R + 2r) = 8