### Home > CCG > Chapter 9 > Lesson 9.1.5 > Problem9-58

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.

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

1. If the interior angles of a polygon add up to $360°$, then the polygon must be a quadrilateral.

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

True

2. If a quadrilateral has $3$ right angles, then the quadrilateral must be a rectangle.

True

3. 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