# Math Help - trignometry

1. ## trignometry

how can we prove that sinA=opp/hyp

2. It is how we define this ratio mate.I don't think that we can prove it.

3. i mean that how can we prove sinA is same in all rt.angled triangles

4. Originally Posted by rohith14
i mean that how can we prove sinA is same in all rt.angled triangles
sides of similar triangles are proportional