Other Modules > Modifying Geometry > To Intersect Geometry
  
To Intersect Geometry
You can divide two entities at their intersection using Intersect. Intersecting two entities creates four entities unless one of the entities is a construction line. If there is more than one possible intersection, such as a spline crossing a line in several places, the intersection closest to your pick point is calculated. You can select a point entity as one of the entities to be intersected.
 
* You cannot intersect construction geometry. However, you can use it to intersect other entities.
1. Click Edit > Trim > Divide.
2. Select the two entities.