Question

Two hemispheres of radius 5cm are attached at the end of a cylinder of same radius .If the height of cylinder is 16 cm then find the surface area of the shape

Answer 1

The shape in this question is formed by a two hemispheres each of radius 5cm and a cylinder of radius 5cm and height of 16cm.  The surface are of each of the hemispheres is,

$A_H =2\pi r^2$.

The surface are of the cylindrical part of the sphere is ,

$A_C=2\pi rh$.

The total surface are of the shape formed by this arrangement is the,

$A_T=A_H+A_C\\\\A_T=2(2\pi r^2)+2\pi rh=4\pi r^2+2\pi rh=4\pi (5)^2+2\pi(5)(16)=260\pi=816.81$.

The total surface are of this shape is $816.81cm^2$