#### Answer

$m = \dfrac{FR}{v^2}$

#### Work Step by Step

Square both sides to obtain:
$v^2=\dfrac{FR}{m}$
Multiply $m$ on both sides to obtain:
$\require{cancel}
m \cdot v^2 =\dfrac{FR}{m} \cdot m
\\mv^2 =\dfrac{FR}{\cancel{m}} \cdot \cancel{m}
\\mv^2=FR$
Divide $v^2$ on both sides to obtain:
$m = \dfrac{FR}{v^2}$