On the ribbon, click
Annotate tab Dimension panel
Dimension .
In the graphics window, select the geometry and drag to display the dimension.
To add a linear dimension for a line or edge, click to select the geometry.
To add a linear dimension between two points, two curves, or a curve and a point, click to select each point or curve.
To add a linear symmetric or linear diametric dimension, select two parallel lines or edges, right-click, and then select Dimension TypeLinear Symmetric or Linear Diametric.
To add a linear foreshortened dimension, select two lines, edges, or points. Then right-click and select Dimension TypeLinear Foreshortened.
To add a radial or diametric dimension, click to select an arc or circle.
To add an angular dimension, select two lines.
To add a foreshortened angular or arc length dimension, select two lines, right-click, and then select Dimension TypeAngular Foreshortened, or Arc Length Foreshortened.
To add a dimension that rotates perpendicular to a selected edge: 1) Select a linear edge or 2 points. 2) Right-click and select Dimension Type Rotated. 3) Select a line to establish parallel or perpendicular direction of the dimension.
To annotate an arc segment with an arc length, angular, or chord length dimension, click to select the arc. Then right-click, and then select Dimension TypeArc Length, Arc Length Foreshortened, Angular, Angular Foreshortened, or Chord Length.
To add an implied intersection dimension, select the first curve, right-click, and then select the intersection. Select the second curve that defines the implied intersection, and then select the element (or other implied intersection) to dimension.
Tip: Selected objects in the drawing determine the type of dimension and commands available in the context menu. To change the settings or use different options, right-click, and click a command on the menu.
Click to place the dimension in the appropriate location.
Tip: When you create a leader line, hold the CTRL key on your keyboard to enable leader line snapping in 15° steps.