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# The Area of a Triangle

## To find the area of a triangle, use the following formula

 Area of a Triangle Worksheet Area of Triangle Applet Area of a triangle Calculator Find Height From Area
The area of a triangle is always  half the product of the height and base.

$Area = \frac{1}{2} (base \cdot height )$

## So which side is the base?

Answer: Any side of the triangle can be a base. All that matters is that the base and the height must be perpendicular.
Any side can be a base, but every base has only one height. The height is the line from the opposite vertex and perpendicular to the base. The illustration below shows how any leg of the triangle can be a base and the height always extends from the vertex of the opposite side and is perpendicular to the base. Play around with our applet to see how the area of a triangle can be computed from any base/height pairing.

The picture below shows you that the height can actually extend outside of the triangle. So technically the height does not necessarily intersect with the base.

## Area of Triangle Applet

See applet on its own page
 Choose Base Side AB Side BC Side AC Formula Type Conventional Heron's



### Explanation of the Area of a Triangle

Example 1
What is the area of the triangle picutred below?
 Area
Practice Problems

Find the area of each triangle below. Round each answer to the nearest tenth of a unit.
Problem 1
What is the area of the triangle in the following picture?

Problem 2
Calculate the area of the triangle pictured below.

Problem 3
Calculate the area of the triangle pictured below.

Problem 4
Calculate the area of the triangle pictured below.

Problem 5
Calculate the area of the triangle pictured below.

Problem 6
What is the area of the following triangle?
Problem 7
What is the area of the following triangle?