Look at the right triangle above. You might be wondering what the weird sign "[math]\theta[/math]" is. [math]\theta[/math] (theta, pronounced "they-ta") is a Greek symbol that is commonly used as a trigonometric variable for the measure of an angle.
"Soh Cah Toa"
Maybe you've heard of the expression "Soh Cah Toa" before. It turns out that that expression relates to Trigonometry!
If we relate [math]\theta[/math] using [math]sin[/math], [math]cos[/math], and [math]tan[/math], we have three new formulas to remember, although they're not too bad.
[math]sin\left(\theta\right)=\frac{opposite}{hypotenuse}[/math]
[math]cos\left(\theta\right)=\frac{adjacent}{hypotenuse}[/math]
[math]tan\left(\theta\right)=\frac{opposite}{adjacent}[/math]
To help you memorize these three formulas, mathematicians have created a catchy phrase: "[i]soh cah toa[/i]." It simply states that "[b]s[/b]in is [b]o[/b]pposite over [b]h[/b]ypotenuse," "[b]c[/b]osine is [b]a[/b]djacent over [b]h[/b]ypotenuse," and "[b]t[/b]angent is [b]o[/b]pposite over [b]a[/b]djacent." Take some time to memorize this phrase.
Remember that the sides change names when you change the angle. However, the trigonometric formulas stay the same!
Review
How do you find the [b]sine[/b] of an angle?
How do you find the [b]cosine[/b] of an angle?
How do you find the [b]tangent[/b] of an angle?