The pressure is given by:
[tex]P=\frac{F}{A}[/tex]In this case the pressure is 30.5 pounds per square cm and the force is 780 pounds, plugging these values and solving for the area we have:
[tex]\begin{gathered} 30.5=\frac{780}{A} \\ A=\frac{780}{30.5} \\ A=25.5738 \end{gathered}[/tex]Hence the total area is 25.5738 square cm. This is the area of both tires, to get the area of just one tire we divide it by two:
[tex]\frac{25.5738}{2}=12.787[/tex]Therefore, the area of contact of one of the tires is 12.8 square cm.