Answer:
r = 1/6
Step-by-step explanation:
[tex]\dfrac{3}{4}r=\dfrac{1}{8}\\\\\\[/tex]
Multiply both sides by 4
[tex]4*\dfrac{3}{4}r=4*\dfrac{1}{8}\\\\3r = \dfrac{1}{2}[/tex]
Divide both sides by 3
[tex]\dfrac{3}{3}r=\dfrac{1}{2*3}\\\\r = \dfrac{1}{6}[/tex]