Question

the circumference of a circle is b inches. the radius of the same circle is 4.5 inches. which expression best represents the value of π?
a $\frac{b}{4.5}$
b $\frac{4.5}{b}$
c $\frac{b}{9}$
d $\frac{9}{b}$

Explanation:

Step1: Recall circle - circumference formula

The formula for the circumference of a circle is $C = 2\pi r$, where $C$ is the circumference and $r$ is the radius. Given that $C = B$ and $r=4.5$.
So, $B = 2\pi\times4.5$.

Step2: Solve for $\pi$

We have $B = 9\pi$. To isolate $\pi$, we divide both sides of the equation by 9. So, $\pi=\frac{B}{9}$.

Answer:

C. $\frac{B}{9}$