Balancing two or three strong forces. Explaining all the points of the lesson, then solving the lesson questions and learning the lesson ideas 1 - Explain the balance of two forces 2 - Balance of two forces on one line 3 - 3 strong balance on one straight line 4 - The balance of 3 is strong, not on the same straight line A - The base of the strong triangle B- The base of the vertical triangle C - Lamy's base