# Trigonometry: The Basics

Over the next few days (Perhaps weeks) I will be doing a series of posts on Trigonometry. I will try to post perhaps once per day excluding weekends. Today we will talk about what Trigonometry actually is and the absolute basics.

What is Trigonometry?

The Word "Trigonometry" comes from the two Greek words "trigōnon", and "metron". "trigōnon" means Triangle and "metron" means measure. Trigonometry is the study of the measure of Triangles.

Trigonometry mainly deals with the relationship of two things in a Triangle: The Angles and the Lengths of the sides.

You might be asking: Why study triangles? why not Quadrilaterals or pentagons or circles?

There is a simple answer to this, it is because A Triangle is Stable.

Try taking 3 toothpicks or pencils or other stright objects and put them into the shape of a triangle. Now try changing the shape of the triangle. You will realise you can't change it, because a Triangle is stable.

Also, If you know the 3 angles in a triangle, the ratios of the sides will always be the same.

Prerequisites

The Pythagorean Theorem

In a Right-angled triangle:

$a^2+b^2=c^2$

Where $c$ is the longest side known as the hypotenuse and $a$ and $b$ are the other two sides

The Next Post in this series will be here

Note by Yan Yau Cheng
5 years, 8 months ago

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"You will realise you can change it, because a Triangle is stable."

TYPO: should be "can't"

- 5 years, 8 months ago

Whoops. I fixed it now

- 5 years, 8 months ago

I like this idea. I am looking forward to future posts.

- 5 years, 8 months ago

@SharkyKesa: The Next post was just posted 1 minute ago here

- 5 years, 8 months ago