Answer to Question 1
Most engineering structures are composed of simple geometric shapes. These fundamental shapes are the basis for manufacturing processes. These geometric features must be provided with location dimensions and size dimensions.
Answer to Question 2
Shrink the object by using one of the drag handles as shown in Figure 5-23, pressing Ctrl / Option to scale about the center. Stop to end the operation anywhere, then use the value comma value format to specify the scale value in both directions