Creating Dimensions Between Concentric Circles and Displaying Extension Lines To dimension between concentric circles and display extension lines: In an open sketch, click Smart Dimension (Dimensions/Relations toolbar) or Tools > Dimensions > Smart. Click the edge of one concentric circle, then click the edge of the second concentric circle. Click to place the dimension. Click . You can also drag extension lines to new attachment points and change the position of radial dimensions. Parent topicDimensions between Arcs or Circles Creating Dimensions Between Two Arcs Changing the Way the Distance is Measured Displaying Extension Lines After Placing Dimensions Changing the Radial Dimension Position Dragging Dimension Attachment Positions