I am using the following code where color and color barlegend show the radius of the concentric circles:
ClearAll[b]
b[x_] := x
Legended[
Graphics[
Table[{Hue[i/20], Circle[{0, 0}, b[i]]}, {i, 1, 6, 0.1}],
ImageSize -> 350, Frame -> True
],
BarLegend[{Hue[#/20] &, {1, 6}}]
]
Can the code be adapted to show the area of the circles instead?