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.

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

Students are taught how to calculate the perimeter of a parallelogram. Extra practice drill problems are also included.

[Free Registration/Login Required] In this lesson, students build geometric models of graduation caps using stiff paper. The activity requires the application of skills in finding surface area, understanding similarity, knowing the...

Explore the world of quadrilaterals and their properties. Find answers to questions like what are quadrilaterals, how they are formed, easy ways to identify them, and commonly seen quadrilaterals around us.

In this activity, students can use the USA TODAY Infograph 'Thirsty for oil' to explore the area of a trapezoid and determine how to find area. Students will find the area of a parallelogram and use this to determine a formula for the...

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

Matrix determinants can be used to solve many algebra and geometry word problems. Among them: finding the area of a triangle, finding the area of a parallelogram, and finding the equation of a line between two points. These three...

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.

Find a quick, concise explanation of a rhombus. An example is given and clearly explained.