Which description is represented by a discrete graph?

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

Ineed your ! i was to turn this into pond first thing i gotta do is outline the inside with this plastic how big should i cut the plastic the height: 10 1/2” the length: 40” the width: 12” me !

Cuántos triángulos forman un diamante