Learn how to find the areas and perimeters of triangles and special quadrilaterals.

This lesson presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.

Geometry concepts are briefly discussed at this site, including volume of a cylinder, parallelograms, circles, trapezoids, and triangles. Sample problems and applications are included for practice.

A complete reference guide to quadrilaterals including squares, rectangles, parallelograms, trapezoids, and rhombus. It provides definitions and interactive activities that enhance further explanation.

Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.

Calculate certain variables of a rhombus depending on the inputs provided. Calculations include side lengths, corner angles, diagonals, height, perimeter, and area of a rhombus.

MathWorld provides multiple definitions and formulas for the mathematical term, square.

Brush up on your math skills relating to trapezoids then try some practice problems to test your understanding.

Brush up on your math skills relating to rectangles then try some practice problems to test your understanding.

Brush up on your math skills relating to rhombuses then try some practice problems to test your understanding.