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Trigonometric Ratios in Geometry
In this hub we are going to be looking at the trigonometric ratios. Here we have a right angled triangle and the angle has been marked as “theta”.
So this symbol equals theta, one of the letters of the Greek alphabet.
Now we will name the sides of the triangle in relation to the symbol theta.
The hypotenuse is always the longest side in a right angled triangle.
Directly across from theta is called the opposite side
The side next to “theta “is named the adjacent side
Sine - Sin S O/H
Cosine - Cos C A/H
Tangent - Tan T O/A
These are the Trigonometric Ratios
You will have to memorise these
An easy way is;
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S O/H C A/H T O/A
For the triangle on the right find;
- Sin θ =
- Tan θ =
- Cos θ =
1. Sin θ = S O/H = 8 / 10
2. Tan θ = T O/A = 8 / 6
3. Cos θ = C A/H = 6 / 10