ABCD is a quadrilateral. The points P, Q, R, and S are the midpoints of the sides of the quadrilateral.
1. Write two correct statements about the lines PQ and AC. 2. What can you say about the quadrilateral PQRS? Explain your reasoning carefully and completely. 3. If PQRS is a square, what can you say about the diagonals of ABCD? Explain how you figured it out.