CK-12 Foundation
Ck 12: Interactive Geometry: 10.4 Slope of Parallel and Perpendicular Lines
Understand how to find the slope of parallel and perpendicular lines.
Lawrence Hall of Science
The Math Page: Skill in Algebra: The Slope of a Straight Line
Here is a site that clearly and thoroughly explains many topics surrounding the slope of a line, including slope of horizontal, vertical, parallel, and perpendicular lines in addition to the formula and concept of slope. There are...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Standard Form of a Line
Dr. Math gives an inspiring and clear discussion about equations of lines and lines as functions. The Dr. discusses the benefits of the standard form of a line and prompts the student with an equation which can not be written in the...
Texas Instruments
Texas Instruments: Investigating the Slopes of Parallel and Perpendicular Lines
In this activity, students investigate how equations of parallel and perpendicular lines relate to each other. They use the drawing and measurement tools of Cabri Jr. to explore the slopes of lines. [Requires Adobe Reader.]
Lawrence Hall of Science
The Math Page: Topics in Pre Calculus: The Slope of a Straight Line
Here is a site that clearly and thoroughly explains the slope of a line. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or...
CK-12 Foundation
Ck 12: Algebra: Determining the Equation of a Line
This comprehensive study guide highlights the main terms and formulas needed to determine the equation of a line. Examples are included.
Varsity Tutors
Varsity Tutors: Hotmath: Slope of a Line
Twenty-two problems present a practice finding the slope of a line. The solutions are only available with a paid subscription.
CK-12 Foundation
Ck 12: Parallel Lines
[Free Registration/Login Required] Students explore the concept of parallel lines by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more about the...
University of Regina (Canada)
University of Regina: Math Central: Introduction to Slope for Middle Years Mathematics
This collection of five middle school math lessons covers the topic of plane geometry, specifically the concept of slope. The first lesson introduces students to plotting points on a Cartesian grid using a Geoboard. Lesson two moves them...
Texas A&M University
Wtamu Virtual Math Lab: Beginning Algebra: Slope
A tutorial on slope with many step-by-step examples. The tutorial clarifies what slope is, how to find slope between two points on a graph, and how slopes of parallel and perpendicular lines are related.
Cool Math
Coolmath: Parallel Lines
This CoolMath resource will help students understand how to use slope and the point-slope form to determine if two lines are parallel.
Texas Instruments
Texas Instruments: Mc Dougal Littell Geometry: Investigate Slopes
Students can use the TI-84 Plus family with Cabri Jr. to investigate properties of parallel lines.
Purple Math
Purplemath: Slope of a Straight Line
This lesson on slope explains the slope concepts, demonstrates how to use the slope formula, shows how to find slope in horizontal and vertical lines, and how to use slope to find whether the lines through the pairs of points are...
Oswego City School District
Regents Exam Prep Center: Slopes and Equations of Lines
Three resources for teaching slopes and equations of lines: a lesson with a formula for finding slope, different equations for lines, and several examples; a fourteen-question quiz covering slope, perpendicular and parallel lines, and...
Illustrative Mathematics
Illustrative Mathematics: G Gpe Parallel Lines in the Coordinate Plane
The goal of this task is to prove the slope criterion for parallel lines. Aligns with HSG-GPE.B.5.
University of Regina (Canada)
University of Regina: Math Central: Characteristics of a Line
Characteristics of a line are explained to students through four different lessons. Topics include intercepts, slope, and special line cases. The lessons have an overview, materials, procedures, and evaluation techniques.
CK-12 Foundation
Ck 12: Algebra: Equations of Perpendicular Lines
[Free Registration/Login may be required to access all resource tools.] This lesson covers determining if two lines are parallel, perpendicular, or neither and finding the equation of perpendicular lines to a given line.
University of North Carolina
University of North Carolina Wilmington: Lines in a Plane
This site from the University of North Caroline at Wilmington provides great information on the lines in a plane. The information that is given is in-depth and complete, touching on the slope of a line, equations of lines, and linear...
ClassFlow
Class Flow: Slope of Parallel Lines
[Free Registration/Login Required] This flipchart investigates the idea that linear equations that have the same slope will create parallel lines. We did some samples in class and then students are to predict what happens when equations...
Khan Academy
Khan Academy: Write Equations of Parallel and Perpendicular Lines
Write the equation for a line that is a parallel or perpendicular to a line given in slope-intercept form and that goes through a specific point. Students receive immediate feedback and have the opportunity to try questions repeatedly,...
Other
Git: What Is the Slope Intercept Form of a Line?
Not only does this site show what the slope-intercept form is, but it helps you find the slope and the intercept of a line. There is also additional information on parallel lines, parametric form, and the distance between two points.
Paul Dawkins
Paul's Online Notes: Algebra: Lines
Detailed math tutorial features notes and examples that discuss graphing lines and introduces the concept of slope, the standard form of the line, the point-slope form, slope-intercept form, and parallel and perpendicular lines.
ClassFlow
Class Flow: Slope of Parallel Lines
[Free Registration/Login Required] Given slope and y-intercept (or a point) can you create the equation for a line parallel to that line (and then graph it)?
Khan Academy
Khan Academy: Parallel and Perpendicular Lines From Equation
Use your knowledge about the slopes of parallel and perpendicular lines to solve some problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.