## IGD: Area of a Triangle

*How Do You Find the Area of a Triangle?*

To find the area of a triangle, find a way to make it look like a shape for which you already know how to find the area. Try to make a parallelogram using a copy of the triangle.

The goal is to create a parallelogram by using a copy of any triangle.

- Change the size and shape of triangle ABC by dragging points
*A*,*B*, and*C*. - Click the
**Make Copy**button to make a copy of the blue triangle. Translate the green copy using point*D*, and rotate it using point*E*. - The
**Show Dimensions**button will complete the problem for you. - The
**Show Dimensions**button indicates the dimensions needed to find the area, and the**Start Over**button resets the drawing.

Use the **Make Copy** button to create a green copy of the blue triangle. Try to arrange the two triangles to form a parallelogram. Translate the green copy using point *D*, and rotate it using point *E*. If you need help, use the **First Move** and **Second Move** buttons to show one way of making a parallelogram. There are also two other ways—can you find them?

- What measurements on the triangle do you need to make in order to find the Area of a Parallelogram?
- What is the area of the triangle?