In the diagram, kl ≅ nr and jl ≅ mr. what additional information is needed to show δjkl ≅ δmnr by sas?
a. ∠j ≅ ∠m
b. ∠l ≅ ∠r
c. ∠k ≅ ∠n
d.∠r ≅ ∠k

B. Angle L=angle R. To prove congruence of triangles by SAS, we need two pairs of sides to be equal, and the included angle equal. We are given KL=NR and JL=MR (the two pairs of sides), then we only need that the angle between KL and JL equals to the angle between NR=MR, so L=R.