Is triangle ABC similar to triangle DEF? Why or why not?

No, because not all corresponding angles are congruent.

Step-by-step explanation:

In order for two triangles to be similar you must have that you know at least 2 corresponding angles are congruent which would also imply the third set of angles are also congruent. You can also tell if two triangles are similar based on their corresponding sides being proportional. Without even checking the proportionally part of corresponding sides, I see the 3 angles in the first triangle do not have the same measurement as the one in the second triangle. Therefore, the triangles cannot possibly by similar.

Hope this helped you love.