Question

on the curved surface of the axis of a globe with the length of 14 cm radius, two circular holes area made each of which has the length of radius 0.7 cm.Calculate the area of metal sheet surrounding its curved surface.

Answer 1

The whole surface area of the globe =`4pixx(14)^(2)` sq-cm.
The areas of the holes `=2pixx(0.7)^(2)` sq-cm.
So the required surface area of the two circular holes
=`{4pixx(14)^(2)-2pixx(0.7)^(2)} "sq-cm."=2pi[2xx(14)^(2)-(0.7)^(2)]`sq-cm
`=2xx(22)/(7)xx(392-0.49) "sq.cm="2xx(22)/(7)xx391.51 "sq.cm"=2660.92`sq.cm
Hence the required surface area of the cicular metalic sheet =2660.92 sq.cm.