EngageNY
Perimeter and Area of Triangles in the Cartesian Plane
Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They...
101 Questions
Best Triangle
What makes an equilateral triangle equilateral? It turns out it's much more than just the side lengths! Learners analyze four different triangles to determine the best equilateral triangle. They create a formula that they later use to...
EngageNY
Perimeter and Area of Polygonal Regions in the Cartesian Plane
How many sides does that polygon have? Building directly from lesson number eight in this series, learners now find the area and perimeter of any polygon on the coordinate plane. They decompose the polygons into triangles and use Green's...
EngageNY
Perimeter and Area of Polygonal Regions Defined by Systems of Inequalities
When algebra and geometry get together, good things happen! Given a system of inequalities that create a quadrilateral, learners graph and find vertices. They then use the vertices and Green's Theorem to find the area and perimeter of...
Radford University
Finding the Largest Possible Area
If you want a bigger garden, here's a task for you. Given the perimeter of a triangular garden, scholars determine the largest possible area. They then generalize their findings and extend the idea to other polygons.
Concord Consortium
Three Rubber Bands
Stretch your mind about triangles. Given a triangle, scholars consider a smaller triangle formed when they stretch three rubber bands from each vertex to the opposite side. They determine the ratios of the areas and perimeters of the...
Curated OER
Principles of Square Roots Lesson Plan
Middle and high schoolers investigate all the different places in math that square root is present. For this geometry lesson, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude, rise,...
Virginia Department of Education
Area and Perimeter
Develop a strategy for finding the area and perimeter of irregular figures. Building on an understanding of finding area and perimeter of rectangles and triangles, learners apply the same concepts to composite figures. After...
Curated OER
Scale Factor Area Perimeter
Mathematicians compare triangles at different scales. In this geometry lesson, high schoolers calculate the area and perimeter of triangles. They use the Ti to make observation of the change that takes place as the triangles are dilated.
Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Curated OER
Area of Triangle using the Semi-Perimeter and Radius
Students investigate the properties of circles. In this geometry lesson, students calculate the area and perimeter of a triangle. They identify the perimeter and radius length of a circle.
Curated OER
Area of Rectangles and Triangles
Eighth graders practice calculating the perimeter of different shapes. As a class, they work together to calculate the area of rectangles and triangles using the proper formula. To end the lesson, they determine how many feet are in a...
Curated OER
Area and Perimeter
Students explore area and perimeter. In this math lesson plan, students differentiate between area and perimeter and compute the area and perimeter of an object.
Curated OER
Ratios of Similar Figures
High schoolers identify the ratios of different triangles. In this geometry lesson, students identify the similarity and differences of triangles. They use the navigator to move the sides of the triangle around.
Mathematics Assessment Project
Evaluating Statements About Length and Area
Class members complete an assessment task by identifying whether statements about triangles and quadrilaterals are always true, sometimes true, or never true. They then participate in a sorting activity with the same objective.
EngageNY
Applications of the Pythagorean Theorem
Begin seeing the world through the lens of geometry! Use the 19th installment in a 25-part module to apply the Pythagorean Theorem to solve real-world problems. Individuals sketch situations resulting in right triangles such as the...
Curated OER
The Value of Volume
Students measure the perimeter and area of their polygons. In this geometry lesson, students calculate the volume and area using the correct tools. They calculate the time and temperature and the perimeter and side lengths of triangles.
Mathematics Vision Project
Module 5: Modeling with Geometry
Solids come in many shapes and sizes. Using geometry, scholars create two-dimensional cross-sections of various three-dimensional objects. They develop the lesson further by finding the volume of solids. The module then shifts...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Curated OER
Which container holds a larger amount of popcorn?
What does popcorn have to do with math? Seventh grade mathematicians are provided an opportunity to develop a conceptual understanding of the formula for volume and to use it as a tool to solve problems. The lesson begins with a...
Mathematics Assessment Project
Pythagorean Triples
What special relationships exist in right triangles? In the high school performance task, learners investigate Pythagorean triples. They then determine rules for the perimeter and area of right triangles given the shortest side.
Curated OER
Roofing and Right Triangles
Learners use models and symbols to represent properties of the Pythagorean Theorem. In this right triangle lesson, students connect real jobs to properties of right triangles. They solve word problems applying the correct ratios and...
Curated OER
Investigating the Sierpinski Triangle
Young scholars solve and analyze the sierpinski's triangle. In this geometry lesson plan, students identify properties and theorem of triangles. They solve problems involving angles and sides of triangles.
Curated OER
Up For Change?
Students explore similar objects. They participate in a series of hands-on, multimedia and online activities to examine how the edge length affects the angle measures, perimeters and areas of similar regular polygons. Students find the...