The center-to-center dimension for a 45-degree bend is equal to the desired size of the offset times the cosecant 1.414. A cosecant is used to determine the distance between the centers of the two bends used to make an offset. A 45-degree angle has a cosecant of 1.414.
An angle's cosecant is defined as the length of the hypotenuse of a 90-degree triangle divided by the length of the opposite side of the triangle. According to the Porcupine Labor Press, other popular offset angles and their cosecants include 10 degrees with a cosecant of 5.76, 22.5 degrees with a cosecant of 2.6, 30 degrees with a cosecant of 2.0 and 60 degrees with a cosecant of 1.15.