# 1819 C2X §6.1

Which exercises/theories should we discuss on the board?
1 / 20
Slide 1: Woordweb
WiskundeMiddelbare schoolhavo, vwoLeerjaar 2

In deze les zitten 20 slides, met interactieve quiz en tekstslides.

Lesduur is: 50 min

## Onderdelen in deze les

Which exercises/theories should we discuss on the board?

#### Slide 1 -Woordweb

Shorter sides & hypotenus
All right-angled triangles have 2 shorter sides and 1 hypotenuse.

The hypotenuse is the longest side and always lies opposite the right angle.
The shorter sides are (as the name suggests)
shorter than the hypotenus and always lie
on either side of the right angle.

#### Slide 2 -Tekstslide

Exercise 2
2a) Which sides are the shorter sides
of triangle ABC?

#### Slide 3 -Tekstslide

Exercise 2
2a) Which sides are the shorter sides
of triangle ABC?

AB and AC

#### Slide 4 -Tekstslide

Exercise 2
2b) Calculate the area of square
ACHI and the area of square ADEB

#### Slide 5 -Tekstslide

Exercise 2
2b) Calculate the area of square
ACHI and the area of square ADEB

area ACHI = 3 x 3 = 9
area ADEB = 4 x 4 = 16

#### Slide 6 -Tekstslide

Exercise 2
2c) Calculate the area of square
BFGC by enclosing the square

#### Slide 7 -Tekstslide

Exercise 2
2c) Calculate the area of square
BFGC by enclosing the square

Area BFGC = 25

#### Slide 8 -Tekstslide

Exercise 2
2d) Add the areas of square ACHI
What do you notice?

#### Slide 9 -Tekstslide

Exercise 2
2d) Add the areas of square ACHI
What do you notice?

9 + 16 = 25.
This is the same as the area of BFGC

#### Slide 10 -Tekstslide

Exercise 2
2e) Calculate the lenght of BC

Area of the square is 25, so the
lenght of BC =

#### Slide 11 -Tekstslide

Pythagoras' theorem
In exercise 3 you will find out that it is always true that if you put a square on each side of a right-angled triangle, the area of the smaller squares added up is the area of the biggest square. This is Pythagoras' theorem:

If a and b are the short sides of a right-angled triangle and if c is the hypothenuse, then:

#### Slide 12 -Tekstslide

Calculating unknown sides
Using Pythagoras' Theorem, you can calculate
the 3rd side of a triangle, if you know the
lengths of the other two sides.

#### Slide 13 -Tekstslide

Calculating unknown sides
We can use this scheme, to fill in everything

#### Slide 14 -Tekstslide

Calculating unknown sides

#### Slide 15 -Tekstslide

Calculating unknown sides

#### Slide 16 -Tekstslide

Calculating unknown sides

#### Slide 17 -Tekstslide

Calculating unknown sides

so PR = 12

#### Slide 18 -Tekstslide

Using Pythagoras' Theorem
When using Pythagoras' Theorem, you need to make sure:
- Your triangle is a right-angled triangle
- You know which sides are the short sides and which side is the hypotenuse, so you can add/subtract the correct squares.

#### Slide 19 -Tekstslide

HW Tuesday
Make and correct §6.1