Number theory GCD relatively prime question

1. The problem statement, all variables and given/known data

let m|d, n|d and gcd(m,n) = 1. show mn|d



2. Relevant equations

gcd(m,n) = d = mx + ny for x and y in integers



3. The attempt at a solution

d = mr

d = ns

1 = mx + ny

1 = (d/r)x + (d/s)y

I don't know, a bit lost,...



Number theory GCD relatively prime question

Number theory GCD relatively prime question