Is 2.3 and 6.5 equivalent?

A20? -foot ladder is placed against a vertical wall of a? building, with the bottom of the ladder standing on level ground 19 feet from the base of the building. how high up the wall does the ladder? reach?

Which equation represents the function on the graph?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.