Can someone answer. there is a picture. it is only one question. you so much!

Well, here's the thing:  If you knew the Pythagorean Theorem,
then you'd have an easy time telling the correct statements of
the Pythagorean Theorem from the incorrect ones.

On the list of choices in the picture, the first three of them are
completely wrong. 

The last one is the correct one, but even that one is misleading. 
The way it's worded, it sounds like a right triangle has more than two legs,
and that you can choose any two of them to work with.  Actually, a right
triangle has exactly two legs, no more and no less, and those are always
the two that you have to work with.