Find the cost of painting the outside surface of a solid cylinder of diameter 7m and height 20m at Rs 5 per m2.
Diameter of the solid cylinder =7m
Radius of the solid cylinder =72=3.5m
Height of the solid cylinder =20m
Painting the outer surface of the cylinder=Total surface area of the cylinder
⇒Total surface area of the cylinder=2πr(r+h)
=2×227×3.5×(3.5+20)
=227×7×23.5
=22×23.5=517sq.m
Cost to paint 1sq.m=Rs.5
Cost to paint 517sq.m=Rs.5×517=Rs.2,585