Answer:
The constant of variation is
![k= 5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7eb4zzt32zqi7a35m75bw2awtf8h3zfuzb.png)
Explanation:
First we must write the relationship as an equality.
If q varies inversely with the square of m, this means that when m ^ 2 increases then q decreases.
If q varies directly with the product of r and x this means that when r * x increases q increases.
Then the relationship is:
![q = k(rx)/(m^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/k8hbi410l78oe3jpvm4rgjag7ec4cvfd3g.png)
Where k is the constant of proportionality
Then if:
![q=2.5\\\\m=4\\\\r*x=8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/63pswhvnfib6w8htcarcf3i7egnqzl587l.png)
![2.5 = k(8)/(4^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jpyqcb8f0nl82p7wvqqmdiqf7bikw8sktm.png)
We solve for k
![2.5 = k(8)/(16)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e51kovvn5scka66bpkaxk3uajdgrozwijw.png)
![2.5 = k(1)/(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fpn5xsfn85pzmyve8ywdswzqsiq9xkncfx.png)
![k= 5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7eb4zzt32zqi7a35m75bw2awtf8h3zfuzb.png)