Rationalizing denominator_9SISC

Rationalizing denominator (Part 1)

it is making your irrational denominator rational.

workplan

• Daily routine

• Anchor Task

• Discussion

• Exercises

Objective:

You need to answer the following questions:

• What is rationalizing denominator?

• What is a conjugate?

• How do we rationalize denominator?

• Why do we need to rationalize denominator?

What is Rationalizing Denominator?

Open Ended

Why do we rationalize denominator?

Open Ended

How do we rationalize denominator?

Multiple Choice

What number should we multiply to make it a rational number?

 $\sqrt{3}$  

•  $\sqrt{7}$  

•  $\sqrt{5}$  

•  $\sqrt{3}$  

Multiple Choice

What number should we multiply to make it a rational number?

 $\sqrt{5}$  

•  $\sqrt{7}$  

•  $\sqrt{5}$  

•  $\sqrt{3}$  

Multiple Choice

What number should we multiply to make it a rational number?

 $\sqrt{2x}$  

•  $\sqrt{2x}$  

•  $\sqrt{x}$  

•  $\sqrt{2}$  

Multiple Choice

Simplify:

 $\frac{2}{\sqrt{5}}$  

•  $\frac{\sqrt{5}}{2}$  

•  $\frac{2\sqrt{5}}{\sqrt{25}}$  

•  $\frac{2\sqrt{5}}{5}$  

Multiple Choice

Simplify:

 $\frac{6}{\sqrt{6}}$  

• 1

•  $\sqrt{6}$  

•  $\frac{\sqrt{36}}{6}$  

Multiple Choice

Simplify:

 $\frac{12}{\sqrt{8}}$  

•  $\frac{12\sqrt{8}}{8}$  
  

•  $3\sqrt{2}$  

•  $\frac{3\sqrt{8}}{2}$  

How do we rationalize denominator if its a binomial?

Open Ended

What is a conjugate?

Multiple Choice

What is the conjugate of

 $\sqrt{2}+\sqrt{3}$  

•  $\sqrt{2}+\sqrt{3}$  

•  $\sqrt{3}-\sqrt{2}$  

•  $\sqrt{2}-\sqrt{3}$  

Multiple Choice

What is the conjugate of

 $\sqrt{x}-\sqrt{y}$  

•  $\sqrt{y}-\sqrt{x}$  

•  $\sqrt{x}+\sqrt{y}$  

•  $\sqrt{x}-\sqrt{y}$  

Multiple Choice

What is the conjugate of

 $2-\sqrt{a}$  

•  $\sqrt{a}-2$  

•  $2-\sqrt{a}$  

•  $2+\sqrt{a}$  

Multiple Choice

Simplify

 $\frac{2}{\sqrt{2}-\sqrt{3}}$  

•  $2\sqrt{2}-\sqrt{5}$  

•  $-2\sqrt{2}+2\sqrt{3}$  

•  $2\sqrt{2}-2\sqrt{3}$  

Multiple Choice

Simplify

 $\frac{2}{\sqrt{3}\ -5}$  

•  $\frac{-\sqrt{3}-5}{11}$  

•  $2\sqrt{3}-10$  

•  $\frac{2\sqrt{3}+10}{-22}$  

Summary!

Guide questions:

• What is rationalizing denominator?

• What is a conjugate?

• How do we rationalize denominator?

• Why do we need to rationalize denominator?

Open Ended

Describe your feeling about our discussion today? Is it too hard? Too easy? Or you need more exercise? Share your ideas. <3