This lesson presents the idea that the area of any triangle is exactly half of a certain parallelogram -- thus we get the familiar formula of multiplying the base and the altitude and taking half of that. The lesson contains varied...

Demonstrates how to calculate the area of two-dimensional shapes using formulas. Covers parallelogram, triangle, trapezoid, and circle. Includes a video modeling how to find the area of a circle and a triangle. [0:59]

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

Brush up on your math skills pertaining to parallelograms then try some practice problems to test your understanding.

In this set of worksheet activities, students will be guided to discover formulas for area of polygonal shapes and circles.

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.

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.