hr2 (3–√−π2)(3−π2) The bases of the three cylinders when placed as given are as shown in the figure : Let the radius of the base of each cylinder = r cm. We are required to find the volume of air. Space left between the cylinders = Area of shaded portion x height of cylinder Now, area of shaded portion = Area of ΔABC – Sum of areas of sectors of the three bases ΔABC, as can be seen is an equilateral triangle of side 2r. ∴ Area of Δ ABC = 3√4×(2r)2=3–√r234×(2r)2=3r2 Area of (sector AEF + sector BED + sector CFD) (∴ sector angles ∠A = ∠B = ∠C = 60º) = 3 x 60o360o×πr2=πr2260o360o×πr2=πr22 ∴ Required volume = (3–√r2−π2r2)h=(3–√−π2)r2h.