One way a shape can be special is to have two congruent sides. For example, an isosceles triangle is special because it has a pair of sides that are the same length. Think about all the shapes you know and list the other special properties shapes can have. List as many as you can. Be ready to share your list with the class at the beginning of Lesson 7.3.1.
Start by making a list of all the shapes you know. Then list each of their special properties.
Refer to the glossary and Math Notes boxes for help.