Square Minus Inscribed Circle
Compute the four corner gaps
An 8×8 pizza with the largest possible circle carved out. Tap each of the four corners to shade them, then enter their combined area.
Composite Figure
Tap the regions to shade, then enter the area. Outer side = 8, radius = 4.
0 / 4 shaded
Tap target regions
Tip: green = shaded, blue = unshaded. Tap a region again to unshade it.