Curated OER
Exploring Polygons and The Greedy Triangle
Excellent lesson plan! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes),...
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...
Curated OER
Identify Polygons: Algebra/Geometry Institute
Eighth graders classify geometric figures. In this polygon lesson, 8th graders identify given geometric figures. They compare and contrast different polygons. Students name line segments, identify parallel lines, and interesections. ...
EngageNY
Cyclic Quadrilaterals
What does it mean for a quadrilateral to be cyclic? Mathematicians first learn what it means for a quadrilateral to be cyclic. They then investigate angle measures and area in such a quadrilateral.
Illustrative Mathematics
Sum of Angles in a Polygon
How can learners use algebra to solve a geometry problem? Help learners create an equation that shows the relationship between the number of sides of a polygon and the sum of the interior angles. Students are asked to divide the...
Curated OER
An Introduction to Quadrilaterals
Students explore the concept of quadrilaterals. In this quadrilateral lesson, students play with a floor tile applet to see that there are many types and characteristics of quadrilaterals including parallelograms, trapezoids, rectangles,...
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...
Curated OER
Areas of Polygons
Young mathematicians calculate the area of polygons in this algebra lesson plan. They find the determinant as they calculate the areas for triangles and quadrilaterals. They also use scalar multiplication to find the determinant.
Curated OER
Diagonals of Quadrilaterals
Teach your mathematicians how to identify different polygons based on their diagonals. Relating quadrilaterals to the different number of diagonals formed, students use the TI to create a visual of their shape.
Curated OER
An Introduction to Quadrilaterals
Learners explore different types of quadrilaterals. Students define the terminology used with quadrilaterals. They create particular quadrilaterals based on specific characteristics of the quadrilaterals using an online tool.
Curated OER
Problem Solving Using Power Polygons
Students investigate geometric shapes by creating figures on a plane. In this polygon lesson, students complete a worksheet based on the angles in a power polygon. Students identify the different types of polygons and define their...
Illustrative Mathematics
What is a Trapezoid? (Part 2)
This collaborative activity investigates the meaning of a trapezoid and a parallelogram. It begins by presenting two different definitions of a trapezoid. Learners are to reason abstractly the difference between the two definitions and...
Curated OER
Interior and Exterior Angles of Polygons
Young scholars identify interior and exterior angles of polygons. In this geometry lesson, students add interior and exterior angles of polygons. They use angle theorems to solve the problems.
Curated OER
Quadrilateral within Quadrilaterals
Students investigate the properties of quadrilaterals. In this geometry lesson, students solve problems dealing with construction and designs. They work with quadrilaterals, midpoints and parallelograms.
Curated OER
Diagonals to Quadrilaterals II
Pupils identify the properties of different polygons. In this geometry lesson, students find the slope of a line and calculate the distance between two lines. They differentiate between similar and congruent polygons.
Curated OER
Patterns in the Sums of Polygon Angles
Sixth graders discover the patterns of sums of polygon angles. In this math lesson, 6th graders study the properties of geometric shapes to solve problems as they participate in hands-on activities.
Curated OER
Areas of Trapezoids, Rhombuses and Kites
Students calculate the area of different polygons. In this geometry lesson, students find the area for trapezoids, rhombuses and kites.
Curated OER
Investigating Area Relationships
Learners investigate the area of various figures. They construct triangles and quadrilaterals using Cabri Jr. and discuss the relationships between different angles, side lengths, and figures.
Curated OER
IGD: Perpendicular Bisector
Students draw perpendicular bisectors. In this perpendicular bisectors lesson, students identify the perpendicular bisector in a polygon. They use web tools to create and measure perpendicular bisectors. Students identify lines of...
Curated OER
Meet the Polygon Family
Fourth graders investigate regular polygons. In this regular polygon lesson, 4th graders explore the attributes of different polygons. Students work in groups to complete a KWL chart regarding polygons.
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.
Noyce Foundation
Lyle's Triangles
Try five problems on triangles. Levels A and B focus on shapes that can be created from right triangles. Level C touches upon the relationship between the area of a six-pointed star and the area of each triangle of which it is composed....
Curated OER
The Very Busy Spider
Youngsters explore visual arts by participating in a geometry identification activity. They read the book The Very Busy Spider and identify the techniques spiders use to create webs. Have you ever noticed that their webs are geometric...
Curated OER
Inscribed Quadrilaterals and Parallelograms
Learners differentiate between inscribed quadrilaterals and parallelograms. In this geometry lesson, students identify the shaped of the polygons when it is inscribed inside of a circle. They calculate the missing angles of the inscribed...