Help learners understand that perimeter and circumference are one in the same. Learners apply their skills to determine the perimeter/circumference of triangles, rectangles, and circles. They then use the same strategy to find the...

Use several shapes to practice finding the perimeter and area. Each page presents examples of different items, including money, the floor plan of a room, and a parking lot.

Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...

Scholars can use area formulas, but can they apply what they know about area? The lesson challenges learners to think logically while practicing finding area of shapes such as rectangles, circles, parallelograms, triangles, and other...

An informative lesson contains a brief explanation of how the sum of the angles of a triangle is a line. The lesson continues with determining the missing angle in a triangle, or solving for a variable. Using the sum of the...

Design and build a rover ... then eat it? This activity has groups of two design and build Mars rovers. The teams determine what instruments they want to include with their rover and plan a budget. They calculate the cost of the body of...

Learn about the perimeter of a polygon with this resource which offers detailed explanations, examples, and an interactive. Subjects covered include how to find the perimeter. Links to related topics.

Find a quick, concise explanation of perimeter. Perimeter formulas are given for common plane figures.

Learn how to find the area of triangles without right angles. Find the formula to use depending on the information you know about the triangle: base and height, three sides, or two sides and an angle.

A complete reference guide to finding the area of a square. It provides definitions, examples, and interactive activities that enhance further explanation. Includes links to related topics.

This fifth-grade lesson explores the area of a rectangle with fractional side lengths. We tile the rectangle with unit rectangles and show that the area is the same as would be found by multiplying the side lengths. We multiply...

Find a quick, concise explanation of circumference. The formula for finding the circumference of a circle is explained.

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

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