Use the formula for the area of a circle:
[tex]A=\pi\cdot r^2[/tex]First, we need to find the radius r. Since the radius is half the diameter, then:
[tex]\begin{gathered} r=\frac{10.5\text{ in}}{2} \\ \therefore r=5.25in \end{gathered}[/tex]Substitute the value for r in the formula for the area of the circle:
[tex]\begin{gathered} A=\pi\cdot(5.25in)^2 \\ \approx86.6in^2 \end{gathered}[/tex]Therefore, the area of a circle of diameter 10.5 in is approximately 86.6 squared inches.
