$\\frac{1}{4}r = \\frac{5}{36}$

$\frac{1}{4}r = \frac{5}{36}$

Multiply both sides by 4:
$$4 \times \frac{1}{4}r = 4 \times \frac{5}{36}$$

Simplify the expressions:
$$r = \frac{20}{36} = \frac{5}{9}$$

$r = \frac{5}{9}$