15 The Basics of Triangles
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You might be asking yourself right about now “Why do we learn about triangles in the trades?” Didn’t we finish with those way back in grade school?” Well believe it or not there are many situations where components or parts of systems in the trades have a triangle in their shape.
Knowing how to calculate the lengths of the sides of those triangles and even the angles involved might just come into play during your trades career.
A good example of that would be a set of stairs. Take a look at the set of stairs to the left and note any triangle formed from those stairs.
A carpenter making stairs will be required to know how many stairs will be in a stair case. He or she will also be required to know the height of the stairs as well as how the stairs are sloped. All in all the carpenter ends up using math, angles and triangles in the calculations.
Another example would be when steam fitters are running pipe which changes direction. This change in direction is what is known as an offset. The change in direction might be 30 degrees, 60 degrees or 45 degrees. The properties of triangles are then used in order to calculate the dimensions of that offset.
Let’s start by identifying the parts of a triangle.
Parts of a Triangle
As we all know a triangle has three sides and those sides have a relationship with each other depending on the angles between them.
The main characteristic of a triangle (other than the fact that it has three sides) is that the three angles within the triangle always add up to 180 degrees. No exceptions.
This means that angle “A” plus angle “B” plus angle “C” will add up to 180 degrees. If we know two of the angles it automatically means that we know the third.
For our purposes we will always be dealing with what is known as a right triangle. A right triangle is one in which one of the angles is 90 degrees. Take a look at the figure below to see what I mean.
In the figure to the left angle “B” is the right angle meaning that it’s 90 degrees.
This also means that angle “A” and angle “C” must add up to 90 degrees to make a total of 180 degrees.
The right angle is always identified by the box that it is enclosed in. Angles other than 90 degrees will be represented by a curved line.
The sides of the triangle also have names and those names all start with what is known as the identified angle. The identified angle will be the one which has the curved line attached to it. Take a look at the following triangle to see what I mean.
The right angle is always identified but this is not the angle we are referring to.
What we are referring to is angle “A”. It’s identified not only by the letter “A” but also by the curved line enclosing the angle.
This is our starting point.
I’ll give you the names of the three sides before letting you know which ones they are. Se