A graph showing the cost of a pizza and the number of toppings has the following points: (1,5) , (2,6) , (3,7) , (4,8) . Identify which number represents a dependent quantity on the graph.

In this graph, the cost of the pizza is the dependent variable, meaning it depends on the number of toppings. Therefore, the number that represents a dependent quantity on the graph is the cost of the pizza.