The volume of a cylinder is the area of its base's area times the height (you will prove this in Calculus).
Thus the formula you need to use is:
pi * radius^2 * height.
I will let you do your own homework from there.
V = 12,566.37 units3
40 pi cubic inches
the cylinder
Volume = 1/3*pi*202*40 = 16755.16082 or about 16755 cubic feet
volume = base area x height = pi x diameter squared / 4 x height vol = 3.14 x 10 x 10 / 4 x 40 = 3140 cubic feet
The volume is 0.70686 m3
V = 12,566.37 units3
Volume of cylinder: pi*16*40 = 2010.619 cubic cm to three decimal places
40 pi cubic inches
The appropriate formula is radius squared times the height times pi. Applying this formula yields an answer of 2.8 X 103 cubic units of the length units in which the radius and height are expressed. (The number of significant digits is limited, by the input value 40, to two. If the height is considered to be 40.0, then the answer would be 2.84 X 103 )
13,194.7cm2
the cylinder
The volume, V of a right cylinder is Pi*r2*h, where r is the radius and h is the height.So, 400=Pi*r2*10r2 = 400/(10*Pi) = 40/Pir would be the positive square root of 40/Pi ~= 3.568 cm
Volume = 1/3*pi*202*40 = 16755.16082 or about 16755 cubic feet
Outer volume = pi*142*40 cm3 Inner volume = pi*122*40 cm3 Volume of steel = Outer volume - Inner volume = pi*(142 - 122)*40 cm3 = pi*52*40 = 6535 cm3 approx.
volume = base area x height = pi x diameter squared / 4 x height vol = 3.14 x 10 x 10 / 4 x 40 = 3140 cubic feet
Volume of the cylinder made by the excavation is pi x r x r x h, where r is the radius and h is the height. So we have volume is pi x 2.5 x 2.5 x 40 = 785.39 cubic feet and must be the amount of soil removed.