Given that the circumference is 9 pi yd.
We have to find the radius and diameter of the circle.
It is known that the formula of the circumference is given below:
[tex]C=\pi d[/tex]
Since the circumference is 9 pi,
[tex]\begin{gathered} C=9\pi \\ \pi d=9\pi \\ d=9 \end{gathered}[/tex]
So, the diameter is 9 yd.
Now, the radius of the circle is half the diameter.
[tex]\begin{gathered} r=\frac{d}{2} \\ r=\frac{9}{2} \\ r=4.5\text{ yd} \end{gathered}[/tex]
Thus, the radius of the circle is 4.5 yd.
