This week in Math 10, I have chosen to talk about the bare basics of trigonometry.

Trigonometry is the study of triangles within mathematics, and is used for applications such as astronomy and surveying. Trigonometric ratios are an integral part, and refer to the ratios between two sides of a triangle, such as the right triangle below.

It is important to explain the text and symbols you are seeing.

ABC are the different corners of the triangle. Generally, they are any sequence of 3 alphabet letters.

The square in the bottom left corner is a 90° angle (right angle). Only one can be found in a triangle, and it makes it a right triangle.

HYP is the hypotenuse. It is the longest side of the triangle and never has a right angle with any of the other edges.

X is the reference point. It can also be represented by an angle or the letter designation. It determines which edge get the next two appellations.

ADJ is the adjacent side. It is the edge closest to the reference point that is not the hypotenuse.

OPP is the opposite side. It is the edge opposite to the reference point, hence the name.

 

Trigonometric ratios refer to three distinct terms: sine, cosine and tangent. Each can be used to discover the approximate length of one of the two sides used, assuming that the other is known.

Sine (abbreviated as sin) is

Cosine (abbreviated as cos) is

And tangent (abbreviated as tan) is