Learning Objectives: Students will be able to apply knowledge about angle pairs to solve problems involving algebraic expressions.
Prerequisite Knowledge: Students should be able to solve simple algebraic expressions. Students should know which angle pairs are congruent and which angle pairs are supplementary when working with parallel lines cut by a transversal.
Motivational Problem: See diagram in “Other resources”.
Key Ideas: Use substitution: If &ang 1 &cong &ang 2 and m &ang 1 = 3x and m &ang 2 = 90 then 3x = 90. Corresponding angles, alternate interior angles, and alternate exterior angles are congruent. Consecutive interior angles are supplementary.
Important Questions: How can we determine whether or not lines are parallel?