Question 1071500
Let {{{R}}} be the earth's radius,
The length of the original band is,
{{{L=2pi*R}}}
So the new length with the change in radius of dR would be,
{{{L+10=2pi*(R+dR)}}}
Substituting,
{{{2pi*R+10=2pi*R+2pi*dR}}}
{{{2pi*dR=10}}}
{{{dR=10/(2pi)}}}
{{{dR=5/pi}}}{{{ft}}}