Website
National Council of Teachers of Mathematics

The Math Forum: Drexel Math Forum: Distance to an Object

For Students 9th - 10th
Dr. Math offers a way to calculate the altitude of a triangle using only the lengths of the sides of the triangle. He briefly explains how this was used by the Egyptians long ago.
Activity
National Council of Teachers of Mathematics

The Math Forum: Drexel Math Forum: Pythagorean Theorem

For Students 9th - 10th
Dr. Math explains how to find distances indirectly by using the Pythagorean theorem.