If P=(3,1) and Q=(-3,-7), find the
midpoint of segment PQ.

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?

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.

How does reflecting or rotating a figure change the interior angles of the figure?