This interactive applet facilitates discovery of the area of triangle by using sliders to explore the area of triangle as it relates to a corresponding rectangle.
Objectives
G-3.2 Carry out a procedure to compute the area of a triangle.
G-3.3 Analyze how changes in dimensions affect the perimeter or area of triangles

Exploring Area of a Triangle
1. Click the show/hide triangle box to hide the triangle. Move the sliders to a desired number and calculate the area of the rectangle (see area listed on the left).
2. Click the show/hide boxes to show the triangle and hide the rectangle. Notice the area of the triangle listed as well as the length of the base and height.
3. Use the sliders to change the lengths and record all information in the table below:
Length of Base Height Area of Rectangle Area of Triangle
1. What do you notice about the relationship of the areas of the rectangle and triangle?
2. Write separate formulas for the area of a rectangle and area of a triangle:
3. What would the area of 2 triangle be? How does it relate to the rectangle?