### Home > CCG > Chapter 9 > Lesson 9.1.5 > Problem 9-58

Decide if the following statements are true or false. If they are true, explain how you know. If they are false, provide a counterexample. *9-58a HW eTool** *(Desmos). *9-58d HW eTool* (Desmos). Homework Help ✎

If a quadrilateral has two sides that are parallel and two sides that are congruent, then the quadrilateral must be a parallelogram.

If the interior angles of a polygon add up to

, then the polygon must be a quadrilateral.

Review the Math Notes for information about the interior angles of polygons.

True

If a quadrilateral has

right angles, then the quadrilateral must be a rectangle.

True

If the diagonals of a quadrilateral bisect each other, then the quadrilateral must be a rhombus.

Experiment with the construction in the eTool below.

Click the link at right for the full eTool version: CCG 9-58a HW eTool

Experiment with the construction in the eTool below.

Click the link at right for the full eTool version: CCG 9-50d HW eTool