Parallel And Perpendicular Lines
Overview
Two lines on a grid can run side by side forever, or cross at a perfect right angle. Both relationships are captured entirely by gradient, the single number that measures a line's steepness. Once you know how gradients behave for parallel and perpendicular lines, a whole family of coordinate-geometry questions opens up.
In this lesson you will learn that parallel lines share the same gradient, while perpendicular lines have gradients whose product is \(-1\), the negative reciprocal rule. You will use these facts to find the equations of lines through given points, the foundation for perpendicular bisectors, tangents and much else.
Objectives
- Know and use the condition for two lines to be parallel or perpendicular.
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Parallel And Perpendicular Lines. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Two lines are parallel when their gradients are: A. Equal B. Negative reciprocals C. Reciprocals D. Opposite in sign Answer: A
- Two lines are perpendicular when the product of their gradients is: A. 0 B. 1 C. -1 D. Equal Answer: C
- What is the gradient of a line perpendicular to one with gradient 2? A. 2 B. -2 C. 1/2 D. -1/2 Answer: D
- A line is parallel to y = 3x + 2 and passes through (1, 5). Its equation is: A. y = 3x + 2 B. y = -3x + 8 C. y = (1/3)x + 5 D. y = 3x - 5 Answer: A
- The gradient perpendicular to a line of gradient 2/3 is: A. 2/3 B. 3/2 C. -3/2 D. -2/3 Answer: C
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