we are given
An air-filled rubber ball
[tex]d_0=6in[/tex]
[tex]d=7in[/tex]
we can use formula of the average normal strain in the rubber
[tex]\delta =\frac{\pi d - \pi d_0}{\pi d_0}[/tex]
now, we can plug values
and we get
[tex]\delta =\frac{\pi*7 - \pi*6}{\pi* 6}[/tex]
[tex]\delta =0.16667in/in[/tex]...........Answer
