Question

Can someone help me find X?
Picture below.

Answer 1

Oh, and the base for the smaller triangle is parallel to the larger one.

Answer 2

Yes, that was the condition I was searching for!
Now why do you think it is necessary we have that condition?
Well, we need it to prove the similarity of the two triangles, the small and the big one.



Are you getting this? :)

Answer 3

Cause if we don't know they're parallel there is no evidence to prove similarity, right?

Answer 4

Yes, you are right! :D