1. The force of repulsion between two particles is inversely proportional to the square of the distance between them. The formula is given to calculate force based on distance. When the distance is halved, the force doubles. 2. For cones of the same volume, height is inversely proportional to the square of the base radius. The heights and base radii of three cones are given. The heights of the other two cones must be calculated. 3. Several problems are given involving inverse proportions, including calculating unknown variables based on known values and inverse proportional relationships defined by equations.