Question

1. select the postulate or theorem that you can use to conclude that the triangles are similar.

sss similarity theorem
sas similarity theorem
aa similarity postulate

Explanation:

Since $DE\parallel BC$, $\angle ADE=\angle ABC$ and $\angle AED = \angle ACB$ (corresponding - angles). In $\triangle ADE$ and $\triangle ABC$, we have two pairs of corresponding angles equal. The AA (Angle - Angle) Similarity Postulate states that if two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar.

Answer:

AA Similarity Postulate