Math 20-2

Chapter 4 Radicals

Lesson 4.2  Adding and Subtracting Radicals

GOAL

The goal of this lesson is stated at the top of page 184 in your textbook, and is also written below.
Keep this in mind as you work through the lesson material.

Select a strategy to add two radicals.

Explore...

Try to answer the question in the sidebar on page 184.

Note,  you can do this activity and use a ruler to measure the side lengths of the resulting triangle.
If you want to connect with the ideas of this lesson,  you should use the Pythagorean Theorem to calculate the side lengths of the resulting triangle.

Hint:    
It will be easiest if you start with a square that has an even side length.

HINT:	
If you want to compare your work with mine,  use cm grid paper and start with a square that has a side length of 20 cm.

Paper folding

I did the activity myself, using grid paper.   I started with a square with sides of 20 cm.

If you go through all the steps, you get something like this.  It works, but unless you are really careful,  it won’t be super accurate.

The key will be that if you start with a 20 cm x 20 cm square, and do all the folding, in the end you get a bunch of triangles formed by the folds.   Each one of them will be the size that you see below (compared with the original square).   Can you use the dimensions of the original square to find the exact dimensions of the triangle?

Watch

Video Tutorial

Learn About the Math

Information and Examples that present the ideas of this lesson

TEXT Page 184

Read/Work through the Learn About the Math section on Page 184 in your textbook.

Go through this material,  AS BEST YOU CAN,  before you view the video tutorials that follow.

Example 1   Adding radicals

Video Tutorial

Apply the Math  (Examples)

Examples will give you TOOLS for solving problems, and also show you that there may be different ways to approach a question.

YOUR TURN gives YOU the chance to try to do a problem ON YOUR OWN,  using the examples as models.

Example 2  Subtracting radicals

TEXT Page 186

Work through Example 2 on Page 186  in your textbook.

Watch

Video Tutorial

Your Turn

Use the Video Tutorial for help, or to check your work, BUT... you should do your best to do this question ON YOUR OWN FIRST!

Video Tutorial

Example 3  Simplifying radical expression

TEXT Pages 186 - 187

Work through Example 3 on Pages 186 - 187 in your textbook.

Watch

Video Tutorial

Your Turn

Use the Video Tutorial for help, or to check your work, BUT... you should do your best to do this question ON YOUR OWN FIRST!

Video Tutorial

In Summary

Key Ideas and Need to Know 
Presents and summarizes  the main new concepts of the lesson

•	Carefully read through each of the bullet points in this section.

•	If you are unclear about any of these ideas,  ASK YOUR TEACHER FOR HELP!

Practice Problems

Doing Practice Problems

Practice problems reinforce the math presented in this lesson.

•	Work through the practice problems for this lesson.
	These problems are for practice, you don’t need to hand them in!
	(your teacher may assign specific questions for you to complete)

•	Use the answers in the back of the book to CHECK YOUR WORK!

•	If you make a mistake, TRY TO FIX IT!

•	If you need help or want more information, view the video solutions provided.

•	If you still need more help,  CONTACT YOUR TEACHER!

Types of Practice Problems

Check Your Understanding questions require basic understanding of the ideas of the  lesson.

Practising questions will require you to dig deeper for a solution.

Closing  A summary question that often asks YOU to explain ideas in your own words.

Extending questions offer enrichment and extension.

Notes

Question 8,    you could do this with a calculator,  that would make the question pretty easy.
The challenge would be,  do the question without a calculator using your radical skills.

Question 17,    I didn’t do a video for this one.

Video Solution Links

Check your work for every problem you do!
If you make a mistake,  try to fix it!
Use the video solutions for more information.
If a problem still doesn’t make sense, ASK YOUR TEACHER FOR HELP!

({{"Question 1", "Question 2", "Question 3", "Question 4", "Question 5"}, {"Question 6", "Question 7", "Question 8", "Question 9", "Question 10"}, {"Question 11", "Question 12", "Question 13", "Question 14", "Question 15"}, {"Question 16",  , "Question 18", "Question 19", "Question 20"}, {"Question 21", , , , }})