The circle and area

Welcome to maths
Need:
• Book open on p. 127 (you can start with exercise 51)
• Notebook open on an empty page (with a margin)
• Pen
• Pencil (+sharpener and eraser)
• Geo triangle
• Calculator

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Slide 1: Tekstslide
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In deze les zitten 11 slides, met interactieve quizzen en tekstslides.

Lesduur is: 45 min

Onderdelen in deze les

Welcome to maths
Need:
• Book open on p. 127 (you can start with exercise 51)
• Notebook open on an empty page (with a margin)
• Pen
• Pencil (+sharpener and eraser)
• Geo triangle
• Calculator

Slide 1 -Tekstslide

Did you check your homework?
Yes? Continue with ex. 51, 52 and 53 on p. 127
No? First check and correct your homework
Remember the difference between radius and diameter?
Radius
From the centre to the outside of the circle, so 0.5*diameter
Diameter
Line from one side of a circle to the other side through the centre, so the diameter is 2*radius

Slide 2 -Tekstslide

Goal
• To calculate the area of a circle
• Write down calculations in a short and formal way
• Check your work

Slide 3 -Tekstslide

How do you calculate the radius
when you know the circumference?

Slide 4 -Woordweb

Calculate the perimeter of a circle in cm with a diameter of 10 dm.

circumference=πdiameter
C=2πr
area=πradius2
A=πr2

Slide 5 -Open vraag

Calculate the radius of a circle with an area of

49π

Slide 6 -Open vraag

Calculate the diameter of the circle with an area of

25π

Slide 7 -Open vraag

Calculate the radius of a circle with a circumference of

6π

Slide 8 -Open vraag

Calculate the area of the coloured part of the circles.

Answer like this --> 9pi / 36pi.
Share at least one out of two answers.

Slide 9 -Open vraag

Work on...
• exercises 51, 52, 53 and 54 on p. 127
• Check your work after 8 minutes with a different colour
• Copy HW in your planner
• HW: Do ex. 51, 52, 53 and 54 on p. 127

timer
8:00

Slide 10 -Tekstslide

Next lesson
• You have finished and checked your homework
• HW: Do ex. 51, 52, 53 and 54 on p. 127 + uploads LessonUp
• We will work on volume