Illuminations: Area Tool

Area Tool
Use this tool to determine how the length of the base and the height of a figure can be used to determine its area. Can you find the similarities and differences between the area formulas for trapezoids, parallelograms, and triangles?

Instructions
 
Investigate trapezoids, parallelograms, and triangles, using the tabs along the top of the frame. Drag the vertices to explore different sizes of each shape.

The "Add to Table" button can be used to record data in the table, which may be useful in trying to identify patterns.

Exploration
 
Investigate various sizes for each of the different shapes.
  • What is the formula for finding the area of a trapezoid? How is the length of the midline involved in the formula?
  • What is the formula for finding the area of a parallelogram? How is it related to the formula for finding the area of a rectangle?
  • What is the formula for finding the area of a triangle? How is it related to the formula for finding the area of a rectangle?
  

NCTM Resources

Navigating through Geometry in 6‑8

Lessons
National Council of Teachers of Mathematics Thinkfinity Verizon Foundation
More and Better Mathematics for All Students
© 2000 National Council of Teachers of Mathematics
Use of this Web site constitutes acceptance of the Terms of Use

The National Council of Teachers of Mathematics is a public voice of mathematics education, providing vision, leadership, and professional development to support teachers in ensuring mathematics learning of the highest quality for all students. The views expressed or implied, unless otherwise noted, should not be interpreted as official positions of the Council.