Vertical Angles is a task designed for geometry students learning about properties of angles and congruence. The task also works as a good exercise for students to critique arguments and determine what makes a good argument. The task looks specifically at two arguments that must prove why all vertical angles are congruent. Students must recognize that you need more than examples in order to prove a statement. Students are asked to contruct their own arguments after critiquing others.
Microsoft Word version: 912Geometry_VertAngles_Worksheet_ConstructCritique_VerticalAngles