4-2 Directly and inversely proportional

• Wiskunde
• Middelbare school
• havo
• Leerjaar 3

Directly and inversely 

proportional (p. 106)

What you need:

- Textbook, writingbook, iPad

- Pen, pencil, geotriangle

- Calculator

Schoolbags in the cuboard

Phones in the phonebag

Bluetooth 

- ON

- VPN off

Lesson goal

Distinguish between direct and inverse proportionality.

Use proportionality to answer simple questions.

Directly proportional

When variable x is multiplied by, for example three and the variable y also becomes three times greater, the variables x and y are direclty proportional.

Y = c x X

Is 8a a direct proportionality?

1. Yes
2. No

Is 8b a direct proportionality?

1. Yes
2. No

Is 8c a direct proportionality?

1. Yes
2. No

Is 9a a direct proportionality?

1. Yes
2. No

Is 9b a direct proportionality?

1. Yes
2. No

Is 9c a direct proportionality?

1. Yes
2. No

Is 9d a direct proportionality?

1. Yes
2. No

Inversely proportional

When variable x is multiplied by for example 3, and variable y becomes three times smaller, the variables x and y are inversly proportional.

Y x X = c

Is 13a an inverse proportionality?

1. Yes
2. No

Is 13b an inverse proportionality?

1. Yes
2. No

Is 13c an inverse proportionality?

1. Yes
2. No

Is 13d an inverse proportionality?

1. Yes
2. No

Maak nu opgaven:

10, 14, 11, 12