Can someone pls me with diagram 2 i'm confused about how i'm supposed to find the number for the corners like the other two diagrams.

Isn't that interesting? What a neat little problem.

The middle number between a and b = (a + b)/2
The middle number between b and c = (b + c) / 2
The middle number between c and d = (c + d)/2
The middle number between d and a = (d + a)/2

The sum of the numbers in the corners of
diagram 1 =  a + b + c + d Do you agree.

Now look at diagram two. Start by putting a, b, c and d in the corners.
Now remove the brackets from what I found above.
diagram 2 = a/2 + b/2 + b/2 + c/2 + c/2 + d/2 + d/2 + a/2 Now collect all the like terms.
diagram 2 = a/2 + a/2 + b/2 + b/2 + c/2 + c/2 + d/2 + d/2
a/2 + a/2 = a does it not?
b/2 + b/2 = b
c/2 + c/2 = c
d/2 + d/2 = d

The sum of the middle numbers in diagram 2 = a + b + c + d
But that's the same sum as diagram 1, which was what you were asked to prove. You cannot come up with a counter example that will give a different result, at least in the positive integers.

The question provides you with room for a written answer. You are going to have to reproduce in some form what I've put in italics.

Thank you for posting.

What is your question? Are you asking if her equation is correct?