Instructional Unit for Geometry


By Brook Buckelew and Nikki Masson


Right Triangles and Trigonometry

Lesson 5/ Day 5

Trigonometric Ratios

A trigonometric ratio is a ratio of the lengths of two sides of a right triangle. The word trigonometry is derived from the ancient Greek language and means measurement of triangles. The three basic trigonometric ratios are sine, cosine, and tangent, which are abbreviated as sin, cos, and tan, respectively.



Practice Problems

1. Find the sine, coesine, and the tangent of the acute angles of the triangle.


2. A new store is being built. An escalator is planned. It will make an angle of 34 degrees with the floor. If the vertical distance between floors is 14 feet, how long will the escalator be?




If the angle made with the floor is changed to 36 degrees, will the length of the escalator increase or decrease?

So the length of the escalator would decrease as the angle increases.


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