Question

What else would need to be congruent to show that ABC DEF by ASA?

Answer 1

Definition: Two triangles are congruent if their corresponding sides are equal in length, in which case their corresponding angles are equal in measure.
ASA Postulate: If two pairs of angles of two triangles are equal in measurement, and the included sides are equal in length, then the triangles are congruent.
To show that ΔABC is conguent to ΔDEF by ASA you have:

1. $m\angle B=m\angle E=50^{\circ}$;
2. $AB=DE=10$
and you should have the measure equality of second pair of angles, adjacent to the corresponding sides AB and DE:
3. $m\angle A=m\angle D$.

Answer: correct choice is D.

Answer 2

Two figures are said to be congruent when they have the same shape and size or if one object is a mirror image of the other object. The triangles ABC and DEF are congruent when they have equal lengths of the sides and having equal sides, angles should as well be equal with the two triangles. The answer is D.