Explanation:

where k is the constant of proportionality
so to find the constant k we first make k the subject of the relation.

where r is 4 and v is 32

now to find the value of v when r is 5.

now to find the value of r when v is equal to 108. yeah we need to make r the subjects of the relation
![r = \sqrt[3]{ (v)/(0.5) }](https://img.qammunity.org/2024/formulas/mathematics/college/lvi6nfube1v05rgf1k0h7x45aosbjal6j6.png)
![r = \sqrt[3]{ (108)/(0.5) } = 6](https://img.qammunity.org/2024/formulas/mathematics/college/11vuoqlcjv9hp0lihsd0he843enc4eh308.png)