On the command bar, click the Tangent button on the Relationship Types list.
Do one of the following:
If you are replacing a relationship you deleted from an existing part, select the part to be repositioned.
If you are placing a new part into an assembly, select the face to be made tangent to an existing part in the assembly.
Select a part in the assembly.
On the part in the assembly, select the face to which the first part is to be made tangent.
Press Enter.
Tip:
You only can apply the tangent relationship with a fixed offset.
When editing the position of a part, you can use the Flip button on the command bar to flip the position of the part to the other side of the face.