Geometry Revision by Tom Harris

Pythagoras

12harrist — 2016-11-02 09:31:12 UTC

Bitesize Pythagoras

12harrist — 2016-11-02 09:33:57 UTC

12harrist — 2016-11-02 09:36:33 UTC

12harrist — 2016-11-02 09:36:57 UTC

12harrist — 2016-11-02 09:40:57 UTC

12harrist — 2016-11-02 09:42:54 UTC

12harrist — 2016-11-02 09:43:50 UTC

Let's have a look at tan in action. Below is a simple right-angle triangle with a 45° angle marked. Remember "sohcahtoa"!

| By definition ,

tan 45° tan 45° | = opposite÷adjacent= 3÷3= 1

Tan 45° will always equal 1, but only applies to right angle triangles.

12harrist — 2016-11-02 09:44:46 UTC

Let's see tan in action with an unknown angle A:

 | By definition,

tan A° = 1÷4 = 0·25But what is the size of angle A? If we draw the triangle by hand, we can use a protractor to find the size of the angle. In this case about 14°.

So tan 14° = 0·25

12harrist — 2016-11-02 09:45:00 UTC

12harrist — 2016-11-02 09:45:49 UTC

Let's have a look at cos in action. Below is a right-angle triangle with a 60° angle marked and two sides. Again recall "sohcahtoa"!

| By definition, cos 60° cos 60° | = adjacent÷hypotenuse= 1÷2= 0·5

Cos 60° will always equal 0·5, when applied to right angle triangles.

12harrist — 2016-11-02 09:46:44 UTC

Now let's have a look at sin in use. Below is a right-angle triangle with a 30° angle marked and two sides. Recall "sohcahtoa"!

By definition, sin 30° sin 30° | = opposite÷hypotenuse= 4÷8= 0·5 |

Sin 30° will always equal 0·5, when applied to right angle triangles.

12harrist — 2016-11-02 09:48:55 UTC

12harrist — 2016-11-02 09:50:34 UTC