The basics of Trigonometry, or the trigonometric ratios also have practical applications in daily life. Sine, cosine, and tangent can be utilized to find the lengths and angles in world problems that are hard to measure.

A key factor in solving these problems is understanding the two basics forms of an angle: the **elevated** angle, and the **depressed** angle.

- An angle of elevation can be measured from (or above) a horizontal line.

- Often, these angles are represented in word problems by wording such as the angle it forms with the ground.

- On the other hand, an angle of depression is measured by the angle formed below sea level, or below the horizontal line.

An example of an application of the angle of elevation in a world problem is the line of eyesight. For example, if Susan was standing on pavement \begin{align*}30 \end{align*} feet away from a building, and her friend Carl was standing on top of the building, and Susan looked up at Carl, her line of eyesight would and the angle that it makes with the ground the would symbolize an angle of elevation.

An example of a depressed angle would be Susan's line of eyesight if she were swimming at sea level, and saw a fish a five feet to her left and two feet below sea level. The angle that Susan's line of eysight would make with sea level is a depressed angle.

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