Trouble understanding why two lengths are equal

[Weng123]

My teacher drew this graph: It shows that the difference between A and B is that tiny section but then wouldn’t that mean length B and C are equal? But I don’t understand how that can be true since B is the hypotenuse of a right triangle and C is a side of the same right triangle.

Thanks in advance.

 

[blamocur]

I agree with you that this does not make sense. Is it possible that your teacher meant to write A-C but wrote A-B by mistake?

 

[Weng123]

No, she explicitly stated that that part is the difference between A and B

 

[blamocur]

No, she explicitly stated that that part is the difference between A and B

Still does not make sense to me. Unless the height of the triangle is 0.