Since ΔEFG is congruent to ΔJKL, their corresponding angles are congruent (CPCTC). The congruence statement tells you which angles of the triangle correspond; ∠E corresponds to ∠J, ∠F corresponds to ∠K, and ∠G corresponds to ∠L. The measures of all the angles of ΔJKL are given, so you just have to name the angle of ΔJKL that corresponds to ∠E of ΔEFG.
Looking at the congruence statement, ∠J corresponds to ∠E, and the m∠J is 90°. Thus the answer is 90°.
