1TH/vwo §10.3 Enclosing areas

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 1

§10.3 Enclosing areas

This time start yourself:

+ make the first tasks of §11.3, so start with

   exercise 17, etcetera

+ later this Lessonup is continued!

Give your answers for a and b only in the next slide!

So key in two numbers.

area A and area B are .... and ....

Solutions:

a. area rectangle around A is  4 x 4 = 16 grid squares

    area triangle A = 1/2 x 16 = 8

b. area rectangle around B is 5 x 3 = 15

     area triangle B = 1/2 x 15 = 7.5 

Now answer c in the next slide.

Key in only the two numbers.

1. 2 and 7.5
2. 2 and 1.75
3. 2 and 1.875
4. 2 and 2

Solution:

Further explanation area B:

7          x   0.25 =       

                   =    1             = 1.875                      How does this work?!

Use this:    

​2​​1​​

​2​​15​​⋅​4​​1​​=

​8​​15​​

​8​​7​​

cm​2​​

​4​​1​​=0.25

​8​​1​​=0.125

​8​​7​​=0.875

​8​​1​​=0.125

FOTOVRAAG:

+ Make 20 a, b and c in your Notebook now.

+ Take a pic of your work and

+ Send it in in the next slide!

20 a, b,c

Solutions:

Is it always a triangle, the area you have to calculate?

Answer: no.

Next slides show you other shapes too!

 

In this exercise you see:

- al kinds of forms

- even a form with a part in the middle taken out!

   (in the two last cases the white part has to be calculated and 

   subtracted)

- now follows the general way to tackle these tasks

When doing this task,

+ use the 4 step we saw in the last slide.

+ give a complete calculation instead of only the answer

Homework:

Make the tasks from:

17 t/m 22 that you didn't do yet

as always, check your work and send it in in GC