CK-12-Pre-Calculus Concepts

http://www.ck12.org Chapter 4. Basic Triangle Trigonometry

4.7 Area of a Triangle

Here you’ll use the sine ratio to find the area of non-right triangles in which two sides and the included angle measure
are known.
From geometry you already know that the area of a triangle is^12 ·b·h.
What if you are given the sides of a triangle are 5 and 6 and the angle between the sides isπ 3? You are not directly
given the height, but can you still figure out the area of the triangle?

Watch This

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/58150

http://www.youtube.com/watch?v=mBFDq4bPXMs James Sousa: The Area of a Triangle Using Sine

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/58152

http://www.youtube.com/watch?v=Pi56pFy-8HU James Sousa: Heron’s Formula

Guidance

The sine function allows you to find the height of any triangle and substitute that value into the familiar triangle area
formula.