Inverse relationships are of the form xy=k or if you prefer y=k/x so to find the constant we can say:
18(0.25)=k=4.5
So you could say: IR=4.5 or I=4.5/R

<h3><em>i </em><em>hope</em><em> it</em><em> helps</em><em> u</em><em> ☠️</em></h3>
you cant add 3x^2 and 7x + 2 :)
you put it in the correct order by the degree :)