Question

Given ∠ABE = 45° and ∠EAB = 63° in ΔABE and∠MNP= 72° and ∠NMP = 63° in ΔMNP. Are the two triangles, ΔABE and ΔMNP similar? If so, by what criterion?
A) yes, by AA criterion
B) yes, by SAS criterion
C) yes, by SSA criterion
D) no, not possible to tell.

Answer 1

A.) Yes, by AA criterion.

Triangle ABE have these angles: 
∠ABE = 45° ; ∠EAB = 63° ; missing ∠ is 72°

Triangle MNP have these angles:
∠MNP = 72° ; ∠NMP = 63°; missing ∠ is 45°

AA criterion is "angle,angle" criterion. It means that the two triangles have at least two of their angles equal. Since a triangle have a total of 180°, when two of their angles are equal, the 3rd angle is also equal.

As you can see, both triangles have 45°, 63°, and 72° measurement of angles. Thus, they are similar.