The model builder has 4 pieces of balsa wood that are 4 cm, 5 cm, 6 cm, and 7 cm in length. How many different combinations of 3 pieces can be used to make triangles without breaking or cutting the pieces? List the combinations as inequalities.
since there are 4 pieces of wood, you will have 4 combinations. since the sum of the 2 shortest sides need to be more than the longest side the inequalities above are valid.