设小圆半径为r,则大圆半径为1.5r=3r/2
S大圆=π*(3r/2)^2= 9π*r^2/4
S小圆=π*r^2
S大圆-S小圆=5π*r^2/4=62.8
即r^2=16
所以S小圆=16π =50.24
S大圆=36π=113.04