If ∆ABC is congruent to ∆PQR, find the length of QR.
Given that If ∆ABC is congruent to ∆PQR:
The simplest way to prove that triangles are congruent is to prove that all three sides of the triangle are congruent.
When all the sides of two triangles are congruent, the angles of those triangles must also be congruent.
From the triangle ABC, the side BC = 4,
Hence the PQR, the side QR = 4 since they are congruent