# 1st F ch13 ANGLES

CH4 Similarity
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 2

This lesson contains 11 slides, with text slides.

Lesson duration is: 50 min

## Items in this lesson

CH4 Similarity

#### Slide 1 -Slide

Types of angles
Acute angle: between 0° and 90°
Right angle: 90°

Obtuse angle: between 90° and 180°
Straight angle: 180°
Full angle: 360°           (A full angle is also called a full turn)

#### Slide 2 -Slide

Both a straight angle and a full turn look like a straight line. The arc is used to show it is an angle.

#### Slide 3 -Slide

Opposite angles
Opposite angles are the angles on opposite sides of the point of intersection of two lines. Opposite angles are always equal.

#### Slide 4 -Slide

Calculating angles
Calculate the size of all angles.

#### Slide 5 -Slide

Calculating angles
Calculate the size of all angles.

#### Slide 6 -Slide

Sum of the angles
The sum of the three angles in a triangle is 180°
The sum of the four angles in a quadrilateral is 360°

A+B+C=180°
D+E+F+G=360°

#### Slide 7 -Slide

Calculating angles
Calculate the size of angle C.

#### Slide 8 -Slide

Calculating angles
Calculate the size of angle C.
C=1808260=38°

#### Slide 9 -Slide

Special triangles
In an equilateral triangle, all sides are the same length and all angles are 60 degrees.
In an isosceles triangle, two sides are the same length and two angles are the same size.

#### Slide 10 -Slide

Homework Monday
- Make and correct: R1, R3, R4, R5, R6
- Bring your calculator (every lesson!)