Question

how do i find the proportionality of r

Answer 1

Since the graph is a linear function, we're going to use the slope formula solve this: 

Note I am replacing m with k
$k= \frac{ y_{2}- y_{1} }{ x_{2}- x_{1} }$

Inserting 2 points from the graph, let's use (1,8) and (2,16).

$\frac{16-8}{2-1}$

k=8