How to calculate mechanical advantage of a third-class lever?

Divide the distance from the effort to the fulcrum by the distance from the resistance to the fulcrum

The first step is to identify the fulcrum, or the pivot point of the lever. Ask the question: Around what point does the lever rotate?

Next, you need to measure the distance from the effort to the fulcrum. The effort is the applied force by the user. So if the lever is a baseball bat, the applied force comes from the hands on the bat, and the fulcrum would be the shoulders. The distance from the effort to the fulcrum would be the distance from the hands to the shoulders.

After this, you need to measure the distance from the fulcrum to the resistance. If we look at the baseball bat, the resistance is the place where the ball hits the bat. So the resistance distance is the distance from the shoulders to the place where the ball hits the bat.

After you have measured the effort distance and the resistance distance, take the effort distance and divide this by the resistance distance.

If the lever is a class three, the mechanical advantage should be less than one. This means the machine sacrifices force for increased distance or speed. So things like tongs, bats, arms, and fishing poles are all useful tools to gain extra distance and/or speed.