## Saturday, 16 August 2008

### Relationship between Angles of Triangle

In a triangle, there are some angles or sub-divided angles within it which relates to each other in some way. The concept of their relationship is simple.

This post is to highlight the fact that once the principle of angles (in a triangle) is understood, the relationship between the angles become clear and simple.

Let's begin.

In the triangle above, there are a few angles labelled. We will look into their relationship.

(Before we start, we need to know that all angles within a triangle add up to 1800.)

Angle A and B form a right-angle corner.
Therefore, A + B = 900.
And A = 900 - B. ---(1)

Also Angle A = Angle C.
Why?
Since angles B, C is part of a right-angled triangle, ==> B + C = 900.
Therefore, C = 900 - B. ---(2)
From the relation (1) and (2), it proved that Angle A = C.

With the same reasoning, Angle B= Angle D can be deduced easily.

If you follow the reasoning of above, you will see that finding the relationship of angles within a right-angled triangle is a breeze.

Maths is not difficult if you understand its principles.

:D