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CK-12 Foundation
Ck 12: Geometry: Triangles and Quadrilaterals Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide reviews the formulas for area and perimeter of triangles and different kinds of quadrilaterals.
Khan Academy
Khan Academy: Use Pythagorean Theorem to Find Area and Perimeter
Find the area and perimeter of triangles and quadrilaterals by first using the Pythagorean Theorem to find missing side lengths. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or...
Other
Algebra Lab: Areas and Perimeters of Triangles and Special Quadrilaterals
Learn how to find the areas and perimeters of triangles and special quadrilaterals.
OER Commons
Oer Commons: Exploring the Properties of a Triangle
In this lesson plan, students explore properties of triangles. They fold paper to make a triangle and measure its angles. Students also draw triangles with given conditions. Included are examples, discussion questions, and closing...
Annenberg Foundation
Annenberg Learner: Constructing Triangles
Use a "linkage strip" to build triangles with different side lengths. When you build a triangle, see if you can deform it into a different triangle while keeping the side lengths the same.
Mathigon
Mathigon: Geometry: Polygons and Polyhedra: Polygons
This lesson focuses on polygons; a polygon is a closed, flat shape that has only straight sides. Polygons can have any number of sides and angles, but the sides cannot be curved.
Texas Instruments
Texas Instruments: Investigating Area Relationships
The interactive Cabri Jr. geometry application makes it easy to measure the area of triangles and quadrilaterals. In this activity, students will explore some interesting area relationships in quadrilaterals.
Science Struck
Science Struck: Similarity Statement in Geometry With Examples
Models how to write a similarity statement about different types of triangles and quadrilaterals.
Texas Instruments
Texas Instruments: Tessellations and Tile Patterns
Students understand that a tessellation is covering of a plane with a pattern of figures so there are no overlaps or gaps. They draw quadrilaterals and triangles and explore monohedral, dihedral, and trihedral tessellating patterns.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.6 Area or Perimeter of Triangles/ Quadrilaterals
Explore finding and measuring perimeter of figures.
The Math League
The Math League: Figures and Polygons
This site provides definitions of different types of polygons and figures.
Primary Resources
Primary Resources: 2 D and 3 D Shapes
Here is a huge collection of teacher resources for teaching 2-D and 3-D shapes. Includes smartboard and PowerPoint presentations, as well as worksheets and helpful hints.
ClassFlow
Class Flow: Area of Polygons
[Free Registration/Login Required] This flipchart provides students with notes and practice with using formulas for finding the area of triangles and quadrilaterals.
Alabama Learning Exchange
Alex: Have Your Math and Eat It, Too!
In this two-day lesson, students will collaborate to create a healthy pizza using only geometric items that have been precisely measured. Students must identify the items as triangle, quadrilateral (parallelogram), or cube. Next,...
National Council of Teachers of Mathematics
The Math Forum: Problems Library Geometry Triangles
This site contains a wealth of problems that deal with the basic definitions of medians, altitudes, angle bisectors, and perpendicular bisectors or the defining characteristics of the different types of triangles. There are also...
NumberNut
Number Nut: Shapes, Symbols, and Colors: 2 D Shapes
Did you know that two-dimensional shapes are also called polygons? This lesson describes the various 2-D shapes and includes two interactive games to reinforce skills.
Cuemath
Cuemath: Equilateral
Learn all about the basic properties of equilateral. This lesson targets the meaning of equilateral, shows how to construct equilateral shapes, explores some of the equilateral shapes and properties, and how to apply them while solving...
BBC
Bbc: Bitesize: Maths: 2 D Shapes
Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.
Alabama Learning Exchange
Alex: Geometric Man
The students will explore angles, rays, line segments, perpendicular lines, parallel lines, and two-dimensional figures through the use of the book Shape Up! Fun With Triangles and Other Polygons by David A. Adler. They will also...
The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
Illustrative Mathematics
Illustrative Mathematics: G Srt Extensions, Bisections, Dissections in Rectangle
In this task, students must draw a diagram from a verbal description and use their understanding of similar triangles to find the area of a quadrilateral. Aligns with G-SRT.B.5.
Mangahigh
Mangahigh: Pyramid Panic: Basic Shapes to Advanced Geometry
Guide a mummy safely through the burial chambers of a pyramid as you solve length and area problems in basic to advanced geometry. There are four game zones that deal with circles and triangles, quadrilaterals, the Pythagorean Theorem,...
OER Commons
Oer Commons: Pre Assessment
Students solve for missing angle measures by applying what they have learned about types of angles and the angle measures of polygons. Students do a pre-assessment at the end of the lesson.
Geometry Help
Geometry Help: Squares
Explains the basic concept of a square with step-by-step instructions and methods for solving specific problems on your own relating to this topic.