# Trigonometry

## How to Verify Trigonometric Identities

Proving identities is a major part of any trigonometry course. This involves getting one of the equation to be identical to the other side. Try using one of the following strategies to begin, and then use others if necessary to continue the verification process. First, start with what appears to…

## Solve Problems Involving Right Triangles

Many application problems involving right triangles mention the angle of depression and angle of elevation. The angle of depression is angle measured below the horizontal, and may also be called the angle of declination. The angle of elevation is the angle measured above the horizontal (see figure below), and may also be called the angle of inclination. Let’s…

## The Tangent, Sine, and Cosine Ratio

To start, a ratio is a mathematical comparison. In other words, the comparison of any two quantities is called a ratio. Any time you work with fractions, for example, you’re technically comparing the numerator quantity to the denominator: null The Tangent Ratio If you have a right triangle, and you…

## Use Similar Triangles to Solve Problems

Similar triangles are formed when you have two different triangles both sharing the same three angles. This makes their lengths, while different, proportional to one another. This suggests that similar triangles are not congruent figures, meaning that they’re not identical in both length and angles, as shown below.The first video below…