the diamiter is the two out side numbers minused by 3.14
Some symbols are missing. I'm assuming you meant to put in a horseshoe symbol like so

If so, then the contrapositive of that would be

which is the final answer.
The tilde sign

means "not" so writing

means "not q" which is the complete opposite of q.
Answer:
can you click a full photo of this question.
X/4+7=y
x being your "number" and y being the answer