Answer:
[tex] {4r}^{6} = 5 \\ 4r = \sqrt[6]{5} \\ r = \sqrt[6]{5} \div 4 [/tex]
[tex] \frac{4r}{6} = 5 \\ 4r = 5 \times 6 \\ 4r = 30 \\ r = \frac{30}{4} \\ r = 7.5[/tex]
