What are the coordinate of D, if ABCD is to be a trapezium but not a rectangle?​

Samantha swam upstream for some distance in one hour. she then swam downstream the same river for the same distance in only 12 minutes. if the river flows at 4 mph, how fast can samantha swim in still water?

Given right triangle xyz, which correctly describes the locations of the sides in relation to

Can you me find the missing length. i attached an image.