One important note to keep in mind when working with equations is the design intent. Whenever we 3D model anything in SOLIDWORKS, we have to keep in mind the design intent we are aiming for. For example, if we are to sketch a rectangle with a width of 5 millimeters whose length will be 10 millimeters, one question is: should we link the two dimensions with an equation? 

To answer this, we have to ask ourselves what is important. If we intend to always have the length of the rectangle as double the width, then applying an equation stating that would be the better practice. However, if we intend to have the length as 10 millimeters regardless of the width's value, then entering a direct numerical value would be the better practice. The following screenshot illustrates this. The rectangle on the left shows the dimensions input if our priority is to keep the length as double the width while the rectangle on the right shows the dimensions input if our priority is to keep the length as a constant value:

The rectangle example is a very simple one. However, the same principle can carry for more complex parts or multiple parts linked together.

This concludes the topic of equations. We learned what equations are, how to apply and modify them, and finally important considerations with design intent and equations. Now, we can move onto exploring what configurations are within SOLIDWORKS parts modeling.