Here is the answer to your query.
Consider two ∆ABC and ∆PQR. In these two triangles ∠B = ∠Q =
90�, AB = PQ and AC = PR.
We can prove the R.H.S congruence rule i.e. to prove ∆ABC ≅
∆PQR
We need the help of SSS congruence rule.
We have AB = PQ, and AC = PR
So, to prove ∆ABC ≅ ∆PQR in SSS congruence rule we just need to
show BC = QR
Now, using Pythagoras theorems in ∆ABC and ∆PQR
Now, in ∆ABC and ∆PQR
AB = PQ, BC = QR, AC = PR
∴ ∆ABC ≅ ∆PQR [Using SSS congruence rule]
So, we have AB = PQ, AC = PR, ∠B = ∠Q = 90� and we have proved
∆ABC ≅ ∆PQR. This is proof of R.H.S. congruence rule.
Hope! This will help you.
Cheers!!!