2TH §4.1 Square roots

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• Middelbare school
• havo, vwo
• Leerjaar 2

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Write shorter

b  =  12a  -  3  +  a  -  5a

§4.1 Square roots

What's new then?

The operations:    +    -    x    and   :   

are familiar to you by now.

You've known them for a long time.

However in this lesson a NEW OPERATION comes up!

Learning goals

a NEW OPERATION comes up!

You will learn: 

• what the square root of a number is
• how to give a approximation of a square root

Question: What are the 4 areas of these squares?

Key them in from left to right, in the next slide.

The 4 areas are ...

Solution:

the areas are:

1,   4,   9  and  16  grid squares

You see 3 squares lined up here.

Question:

What are the lengths of the 3 different sides?

Key them in in the next slide.

The 3 different lengths are ......

You see 3 squares lined up here.

Question:

What are the lengths of the 3 different sides?

Solution:   the 3 different lengths we see are  5,   9   and     ......  ??! 

Your state of mind now may be best described by the next slide!

This is the one that gave us a

-   headache or a 

-   thrill

Choose whatever applies to you.

Question:

Between which 2 WHOLE NUMBERS

does the length of this square lie?

ANS

Between ... and ...

Question:

Between which two WHOLE NUMBERS does the length of this square lie?

Solution:

Between 10 and 11.    Why?

Because 10 x 10 = 100      and   11 x 11 = 121

SOMETHING NEW NOW:

we call the length of the square's side:

THE ROOT OF 112 !

Get your CALCALATOR now!

Find the ROOT key and KEY IN:

ROOT 7 !

It's clear that   

      7     is not a whole number.

√​​​​

Homework:

§4.1 Square roots

Do exercises 2, 3, 5, 6 and 7 (page 129-130)

Find it difficult? Do the support exercises

Need a challenge? Do the challenge exercises