Graphing Calculator Math Worksheets Algebara Solver Chart Maker
 A+ A− B

# The Area of a Triangle: SAS Formula

## The Side Angle Side Formula

The Side Angle Side formula for finding the area of a triangle is a way to use the sine trigonometric function to calculate the height of a triangle and use that value to find the area of the triangle.
The formula $$=\frac{1}{2} \cdot c \cdot b \cdot sin(\text{A})$$
or, in general
$$Area = \frac{1}{2} \cdot side_1 \cdot side_2 \cdot sin(\text{included angle})$$
Visit this url, if you want to review what is meant by 'included angle'.

## Where does this formula come from

Can you identify which triangle below has an included angle?

Example 1
Step 1) Identify two sides and the included angle!
 Do Step 1
Step 2) Apply the formula!
 Do Step 2

Practice Problems

Step 1) Identify two sides and the included angle!
 Step 1
 Step 2

Step 1) Identify two sides and the included angle!
 Step 1
 Step 2

Step 1) Identify two sides and the included angle!
 Step 1
 Step 2
 Choose Angle A C B All Side Lengths?
Interactive Applet

Explore applet by itself.