Scale

Enlarges or reduces selected objects and keep the object's proportional

Modify panel > Scale

Select object
Press Enter

Specify base point

Specify scale factor: 1.5

Copy option

Repeat Scale command
Pick the same base point
Command line: Copy

Specify scale factor: 0.8

Object scale and make a duplicate object

Reference option

Repeat Scale command
Select the outer object
Press Enter

Pick the same base point

Command line: Reference

Pick the base point as the 1st point

Pick the tip of the object as the 2nd point for the reference length

Specify new length: 3200