CK-12-Pre-Calculus Concepts

4.4. Right Triangle Trigonometry http://www.ck12.org

4.4 Right Triangle Trigonometry

Here you will learn the six right triangle ratios and how to use them to completely solve for the missing sides and
angles of any right triangle.
Trigonometry is the study of triangles. If you know the angles of a triangle and one side length, you can use the
properties of similar triangles and proportions to completely solve for the missing sides.
Imagine trying to measure the height of a flag pole. It would be very difficult to measure vertically because it could
be several stories tall. Instead walk 10 feet away and notice that the flag pole makes a 65 degree angle with your
feet. Using this information, what is the height of the flag pole?

Watch This

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/58116

http://www.youtube.com/watch?v=Ujyl_zQw2zE James Sousa: Introduction to Trigonometric Functions Using
Triangles

Guidance

The six trigonometric functions are sine, cosine, tangent, cotangent, secant and cosecant. Oppstands for the side
opposite of the angleθ,hypstands for hypotenuse andadjstands for side adjacent to the angleθ.
sinθ=o p phy p

cosθ=ad jhy p

tanθ=o p pad j

cotθ=ad jo p p

secθ=hy pad j

cscθ=o p phy p