Question

If triangle ABC ~triangle PQR, AC =15, BC =10, PR =12, then find QR.

Answer 1

You can’t.

We need to find the ratio r between the linear measurements of the two similar triangles. Then PQ+QR will be r(AB+BC) = 10r.

Also r(AC) = PR = 6

So r = 6 / AC

Now we have a problem. All we know about AC (from the triangle inequality) is that AC < 10.

So all know about r is that r > 0.6