Question

# Given the following formula, solve for r. C=2πr A. r=2πC B. r=(C−π)/2 C. r=C/2π D. r=C−2π

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Given the following formula, solve for r. $$\displaystyle{C}={2}π{r}$$
A. $$\displaystyle{r}={2}π{C}$$
B. $$\displaystyle{r}=\frac{{{C}−π}}{{2}}$$
C. $$\displaystyle{r}=\frac{{C}}{{2}}π$$
D. $$\displaystyle{r}={C}−{2}π$$

For $$\displaystyle{C}={2}π{r}$$, the rr is being multiplied by 2π. To solve for r we would then need to divide both sides by 2π since division is the inverse operation of multiplication.
Dividing both sides of C=2πr by 2π gives $$\displaystyle\frac{{C}}{{2}}π={2}π\frac{{r}}{{2}}π.$$
Simplifying then gives C. $$\displaystyle{r}=\frac{{C}}{{2}}π.$$