Question

The diameter of a cylinder is 6 feet 6 inches. The height of a cylinder is 12 feet 3 inches. What is the surface area?    (feet squared) What is the volume?      (feet cubed)
   

Answer 1

$d-the\ diameter\\r-the\ radius\\H-the\ height\\\\d=6ft\ 6"=\left(6\frac{6}{12}\right)ft=6.5ft\\\\d=2r\to2r=6.5ft\to r=3.25ft\\\\H=12ft\ 3"=\left(12\frac{3}{12}\right)ft=12.25\ ft\\\\Surface\ area:\\A_s=2\pi r(r+H)\to A_s=2\pi\cdot3.25\cdot(3.25+12.25)\\=6.5\pi\cdot15.5=100.75\ (in^2)\\\\Volume:\\V=\pi r^2H\to V=\pi\cdot3.25^2\cdot12.25=129,390625\ (in^3)$