Same Size
The Samesize constraint is applied to pairs of geometric elements, which must be of the same geometric type. All elements except for spline-based entities (rational splines, bsplines, and ellipses) and construction lines are eligible for this constraint. The members of a same-size pair will be adjusted as needed by Solve to become the same size. Specifically, the radii of circular elements and the length of linear elements is adjusted. If the members of a same-size pair are not in fact the same size at solve time, Solve will look at other constraints on the members of the pair to determine which member should be changed to match the size of the other.
To assign Samesize constraints:
1. Click Parametric and then, in the Create group, click 
Constraints.
Constraints.The Generate Constraints dialog box opens.
2. In the Action area, click Assign.
3. In the Type box, select Samesize.
4. Click Apply.
5. Click the two elements to be constrained.
6. Click 
OK or assign the next constraint.
OK or assign the next constraint.Each element in a same-size pair is labeled with the same-size icon, , and a reference number that is unique to the pair.