1TTO §5.4 Measuring angles

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

1TH/Vwo §5.4 Measuring angles

First a quick check on your knowledge of §5.3 !

Try to give the good answers, gaining points.

an angle of 90 degrees is a(n) ...

1. straight angle
2. obtuse angle
3. right angle
4. acute angle

An angle of 47 degrees is a(n)
...... angle.

1. obtuse
2. right
3. acute
4. straight

I wonder if    .....

+ you had both right, knowing all about it, or

+ you had both wrong, having no clue

However, let's look back at the relevant Theory from §5.3 !

Schermafbeelding 2020-11-08 om 10.20.17

Schermafbeelding 2020-11-08 om 10.20.33

Ready for §5.4 Measuring angles?

Soon comes a Movie.

First 2 special things:

+  Which angle is meant?

+ How to measure an angle if the arms are too short?

  Just watch the next slides!

In the picture you see many different angles:

+ angles A, C and E , but also

+ angles B1, B2, D1 and D2 !

+ so by the added number you

   know which part of the angle 

   is meant. Great!

If the arms of an angle are too short, just ....

extend them!

So in this case

you take your pencil and 

make both arms longer,

so that the geo can be used well! 

(You may even do this in your Textbook, 

but with a PENCIL, of course!)

Measuring angles ...

+ you can do with the geo triangle

+ using the PROTRACTOR ( =gradenboog),

+ that's the semi-circle (=half a circle) with the degrees from 0 - 180 degrees

    written on it

+ just watch the following Movie and be amazed!

Time for Homework

+ Do:    § 5.4 Measuring angles

+ Check your work with the Solutionsbook

+ Mark the right percentage on your Planner