# Geometry Unit 3: Parallel and Perpendicular Lines

The Geometry Unit 3: Parallel and Perpendicular Lines Unit Module contains seven lessons, each with a video, teacher reference, practice packets and solutions, and corrective assignments. In the first lesson, pupils learn eight definitions dealing with types of lines and angles formed when another line crosses two lines. The second lesson focuses on the relationships of angles when a transversal intersects two parallel lines. Using algebraic skills, individuals calculate the measures of angles in figures. Next, scholars learn the converses of the properties of parallel lines. Using the converses, they determine which lines are parallel based on angle measurements and practice using a flow proof. Lesson four presents two theorems dealing with the angles of a triangle. Pupils learn about the Triangle Sum Theorem and the Exterior Angle Theorem and then apply the theorems to create equations and find missing angles. They also review graphing and writing the equations of lines in slope-intercept form. In lesson six, learners discover the relationship between slopes of parallel and perpendicular lines and use that information to find equations of lines through a given point that is either parallel or perpendicular to a given line. To end the unit, scholars watch a quick review on the Parallel and Perpendicular Lines unit. They then work through ten review problems ranging from identifying angles formed by parallel lines and transversals to writing equations of parallel and perpendicular lines.