Use this calculator to find the sides, perimeter, area, semiperimeter, and altitude of an isosceles triangle.

[Free Registration/Login may be required to access all resource tools.] This study guide reviews terminology for triangles, triangle properties, different types of triangles, and interior and exterior angle theorems.

Discover some theorems about triangles.

Learn about the types of triangles by taking a look at an example and a video lesson.

For this lesson, young scholars learn to classify triangles by the size of the angles and the measures of the sides. Students will use interactives to explore equilateral, isosceles, scalene, acute, obtuse, and right triangles. Included...

Explore polygons with Wang, a ricksha puller. Answer his questions and he will give you a free ride!

The Chinese character mark formerly known as "Tan" is the first of two lessons to introduce first grade students to geometry using tangrams. This lesson incorporates history, math, and language arts. In this lesson students will be able...