Discovering Perimeter

Are all the measurements scalable? Pupils work in groups or alone to determine whether figures are similar and find any missing side lengths. Then, they calculate the perimeters and areas of the figures. Finally, using the measurements,...

Students explore pi. In this circle measurement lesson, students define and identify radius, diameter, circumference, and perimeter. Students work in groups to measure several plastic lids and record their findings. Students compare the...

Students explore properties of triangles.  In the geometry lesson, students construct the centroid, circumcenter, and the orthocenter of a triangle.  The dynamic nature of Geometer’s Sketchpad allows students to discover important...

Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...

Students determine how to find the perimeter of a rectangle. In this perimeter lesson, students make rectangles of given sizes using a 20" string. They record the the length, width, and perimeter of each rectangle. They discover the...

Discover how to find the algebraic formula for the perimeter of a rectangle through this tutorial. Your algebra learners will be guided towards the thinking steps around this concept. After showing the video, invite your class to model...

Consider the relationship between side length and area as an input-output function. Scholars create input-output tables for the area of squares to determine an equation in the first installment of a three-part unit. Ditto for the area of...

Students discover a formula for finding the perimeter of a rectangle by using string. After a lecture/demo, students receive a worksheet with pre-drawn rectangles so they can practice computing perimeter with their string.

Discover the peculiar geometric property of the curve of constant width, the Reuleaux triangle, and their intriguing connection to manhole covers with yet another fascinating TED-Ed video. 

Examine an exponential growth model. Using a fractal, learners calculate the perimeters of each stage. When comparing the consecutive perimeters, a pattern emerges. They use the pattern to build an equation and make conclusions.