Question

The circumference (C) C of a circle is 18 18 centimeters. Which formula can you use to find the radius (r) r if you know that C=2πr C = 2 π r ?

Answer 1

Answer: $\text{r=}\dfrac{9}{\pi}$

Step-by-step explanation:

The circumference of a circle is given by :-

$\text{C=}2\pi r$, r is the radius of the circle.

To write the formula to find radius (r), we nee to divide $2\pi$ on bopth the sides on the above equation, we get

$\text{r=}\dfrac{C}{2\pi}$, where C is the circumference of the circle.

If Circumference = 18 centimeters

Then, the formula to find radius is given by :-

$\text{r=}\dfrac{18}{2\pi}=\dfrac{9}{\pi}$

Answer 2

C = 2πr

r = radius

c = circumference = 18

Plug in the corresponding numbers with variables.

18 = 2πr

Isolate the r. Divide 2 and π from both sides

(18)/2π = (2πr)/2π

9/π = r

C/π = r is your formula to finding r.

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