Use the Dimension command to add only the dimensions you need, then use the Automatic Dimensions and Constraints command to calculate all other sketch dimensions and constraints.

Constrain panel
Automatic Dimensions and Constraints
. The Auto Dimension dialog box shows the number of dimensions and constraints required to fully constrain the sketch.
If you prefer, click and hold the left mouse button, then drag to enclose desired geometry in a selection window, then click to select.
To automatically dimension and constrain the entire sketch, click Apply with no geometry selected.