Answer
r=2.7
Work Step by Step
Use the multiplication property since the variable is in the numerator.
$\frac{r}{2.1}=\frac{3.6}{2.8}$ multiply both sides by 2.1
$\frac{r}{2.1}\times2.1=\frac{3.6}{2.8}\times2.1$ simplify
$r=\frac{7.56}{2.8}$ reduce
$r=2.7$
