2TH/vwo Ch 4 SUMMARY p.144/147

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 2

Today:  Ch 4  SUMMARY p.144/147

After having done § 4.4 we do the SUMMARY.

The great thing about these Summaries is that you are doing tasks, after

studying (once more) just that bit if Theory or Method that you need.

Mention one thing you expect to see in the Summary.
Do not look in the Book!

Open Textbook 2A, p.144/147

An enlargement of a figure

1. is greater
2. basically looks the same
3. is sometimes greater, sometimes smaller
4. has the same angles

Look once more at exercise S6.
What method/instrument is needed to do S6?

1. a calculator
2. a ratio table
3. a X-mas tree
4. a ruler

What's the best approach (=aanpak) for S7 ?

1. Just write down: 'Yes.'
2. 1.calculating unknown angles 2.comparing all angles 3.ratio table for the sides 4.conclusion
3. Working out: + are the angles equal? + do the sides have the same ratio?
4. Just write down: 'No.'

S8 then.

What to do, before making a ratio table. Why?

What and why?!

1. Compare the angles, because that's what the book says.
2. Sketch both figures in the same position, because then you can compare them much better.
3. Sing a lovesong, because you feel so happy...
4. Calculate the scale factor, because that is the key to the rest.

Finally S9!

Compare S9 a and S9 c.

What is the basic difference, as far as the scale factor

is concerned?

Difference between S9 a and S9 c:

1. No difference at all.
2. S9 a is meant for the girls. S9 c is meant for the boys.
3. S9 a is about perimeter. S9 c is about area.
4. In S9 a is about the scale factor. S9 c about scale factor squared.

WHY did we do the previous slides?

Now do the SUMMARY, p.144-147.

Study every 'Theory', 'Skill' or 'Example' carefully, before doing the next exercise!

The only sounds you hear are ....

What did you learn this lesson?