Creating equations using the Parameters Manager
Equations are relations between the dimensional constraints. Look at the drawing given below. In this drawing, all the dimensions are controlled by the diameter of the hole. In AutoCAD, you can create this type of relations between dimensions very easily using the Parameter Manager palette.
Click the Parameters Manager button on the Manage panel; the PARAMETERS MANAGER
palette appears.
Double-click in the box next to the dia1 and enter 50.
Similarly, change the values of the other dimensions as shown below.
You will notice that the circle is placed outside the loop.
Click Zoom All on the Navigation Bar to view the circle.