# Lesson Plan: Equations of Parallel and Perpendicular Lines Mathematics • 11th Grade

This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to write the equation of a line parallel or perpendicular to another line.

#### Objectives

Students will be able to

• identify whether two given lines are parallel, perpendicular, or neither,
• find the equation of a line that is parallel to a given line,
• find the values of the unknown coefficients in the equations of two parallel straight lines,
• use the relationship between the gradient of perpendicular lines in order to find the slope of a line given a line perpendicular to it,
• find the equation of a line that is perpendicular to a given line,
• find the values of the unknown coefficients in the equations of two perpendicular straight lines.

#### Prerequisites

Students should already be familiar with

• the definitions of the terms parallel and perpendicular,
• the slopes of parallel and perpendicular lines,
• writing the equation of a line given the slope and the -intercept,
• writing the equation of a line given the slope and a point on the line,
• writing the equation of a line given two points on the line.

#### Exclusions

Students will not cover

• vector equations of straight lines,
• parametric equations of straight lines.