I am working on this question, and the solution says something weird.
The solution starts by saying
The part I don't get is where they say 'PQR is $9 = 3^2$ to $1$, so the ratio is $3$ to $1$'. How can you square root each side of a triangle and keep it proportional to the other? If you multiplied each side by a number like $4$, the proportionality would stay the same, but if you squared or square rooted, wouldn't the triangles be no longer proportional?
Thanks for the help!