It is an arc that is not concentric with the 40 radius circle. This is assuming that it is a one quarter symmetric part.

By the numbers, there is nothing that indicates it is even an arc, let alone radius or center position. It's a bump that closely resembles an arc. That's all we know.

This is a three-point arch! The drawing is not proportional! Look at the marked dimensions "15" and "30". without measuring, you can see that "30" is greater than 2 x "15".

When converting a vector drawing to a bitmap, such distortions are normal

EDIT

Now, I remind that in old version ACAD (?) you had to set whether the circle should be a circle on the monitor or on the printout!

It is an arc that is not concentric with the 40 radius circle. This is assuming that it is a one quarter symmetric part.