Step 1 :The problem states that Hiro painted his room at a rate of 8 square meters per hour. After 3 hours, he had 28 square meters left to paint. We can use this information to determine the slope and a point on the graph.
Step 2 :The slope of the graph is the rate at which Hiro is painting, which is -8 square meters per hour. The negative sign indicates that the amount of area left to paint is decreasing over time.
Step 3 :The point on the graph is given by the information that after 3 hours, Hiro had 28 square meters left to paint. This corresponds to the point (3, 28).
Step 4 :Therefore, the information given about the graph of the relationship is the slope and a point that is not an intercept.
Step 5 :\(\boxed{\text{The correct answer is (C) Slope and a point that is not an intercept.}}\)