Perimeter and Area of Similar Figures

Students calculate the area and the perimeter of triangles. In this geometry lesson, students identify the ratio and proportion of similar figures.

A triangle, square, hexagon, and circle all have a perimeter of one unit. Eighth graders must attempt to find the area of each and arrange them in order from least to greatest areas. A terrific task for applying four different area...

Making the transition from two-dimensional shapes to three-dimensional solids can be difficult for many geometry students. This comprehensive Common Core lesson starts with writing and graphing linear equations to define a bounded region...

Students explore the concept of scale factors.  In this scale factors lesson, students dilate polygons and determine the ratio of the perimeters and areas of an image and pre-image.  Students use Ti-Nspires to graph triangles, measure...

What is the cross-sectional area of the Orion spacecraft? Groups work together to estimate the area of a cross section of the Orion spacecraft by first counting the number of grids a scale drawing covers. Pupils also employ a method...

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...

Are pyramids and cones similar in definition to prisms and cylinders? By examining the definitions, pupils determine that pyramids and cones are subsets of general cones. Working in groups, they continue to investigate the relationships...

Taking a lesson straight from the calculus classroom and making it algebra appropriate is the task of the day. Learners go step by step through calculating different area approximations underlines and curves, reviewing many key geometry...

As they investigate scaling figures and calculate the resulting areas, groups determine the area of similar figures. They continue to investigate the results when the vertical and horizontal scales are not equal. 

Begin this study on the relationship between area and perimeter with the hook activity featured at the bottom of the "What Shape is Your Land?" link, which offers a fun optical trick to engage high schoolers. Learners should have a basic...