Assuming that the two graphs are not in contact, it means that the two graphs are added and there is contact, which means that the two graphs are subtracted.

The first picture: □+○=3

In the second picture: ○-□= 1, we get ○=2, □= 1.

The third picture: □+△=6, and the result △=5.

The fourth picture: △-□=4

So the fifth picture is delta+○ = 5+2 = 7.