Explore properties of some special quadrilaterals using segments to build quadrilaterals and explore their angles.

• Students will recognize the types of quadrilaterals formed when opposite sides are congruent.
• Students will recognize that there are special quadrilaterals in which consecutive angles are supplementary and opposite angles are congruent.
• Students will recognize that for some special quadrilaterals, opposite sides are parallel.

• parallelogram
• square
• rhombus
• rectangle

This lesson involves properties of parallelograms. Students manipulate endpoints of a set of segments or manipulate angles formed by two segments. As a result, students will:

• Make a quadrilateral (parallelogram) when opposite sides are congruent.
• Investigate a given quadrilateral (parallelogram) to observe that consecutive angles are supplementary and opposite angles are congruent.
• Investigate a given quadrilateral formed by parallel lines.
• Visualize different types of quadrilaterals.
• Infer about the properties of different special quadrilaterals.
• Describe consequences of all segments being congruent.