To find the area of a triangle, try to make a parallelogram using a copy of the triangle.

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]

[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...