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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...
Illustrative Mathematics
Hexagonal Pattern of Beehives
Young geometers and biologists investigate the math of nature in an activity that is just the bee's knees. Participants will study the tessellations of hexagons in a beehive, along with the natural rationale behind the specific shape....
Noyce Foundation
Poly-Gone
Investigate polygons from rectangles to triangles to octagons. Each level of the five-problem series targets a different grade level. Beginning with the level A problem, learners examine the relationship between area and perimeter by...
Curated OER
Shapes and Their Insides
Learners follow a series of instructions for drawing and coloring different shapes in order to learn the difference between the perimeter and area of a polygon. Then they are asked to find the perimeter and area of a 3x4 rectangular...
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...
Teach Engineering
Stay in Shape
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
Illustrative Mathematics
Overlapping Squares
The objective of this activity is to find the percent of the area of a two squares overlapping. Mathematicians find the ratio of area for the part that overlaps to the rectangle formed. The final answer is a percent as a rate per 100....
Curated OER
Life in a Geometrical Town
In this geometry worksheet, students create a map that uses various geometrical concepts. The final project is the creation of a "geometrical town." Rubric for grading is included.
CK-12 Foundation
Ck 12: Area and Perimeter of Triangles
[Free Registration/Login Required] Students are given the base and height of a triangle and are to determine the area and perimeter. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Area and Perimeter of Triangles
[Free Registration/Login Required] Students explore the relationship between and area and the base and height of a triangle. Click challenge me to answer practice questions and click learn more to watch a video.
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
This applet allows users to study the nature of triangles and their area. It draws random triangles on a Cartesian coordinate system. The user can determine the area of the triangle using his or her preferred method. After the calculated...
Texas Instruments
Texas Instruments: Area of Triangle
This Cabri Geometry activity enables students to review the relationship between the height of a triangle and its perimeter and area.
The Math League
The Math League: Area and Perimeter
This tutorial provides a brief introduction about what area is, then gives the formulas for area of a square, rectangle, parallelogram, trapezoid, triangle, and circle. Examples of each formula are provided.
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
Students explore the nature of triangles and their area. An applet and instructor resources are included. [Requires Java.]
National Council of Teachers of Mathematics
Nctm: Illuminations: Igd: Area of a Triangle
Use this interactive tool to learn how to find the area of a triangle. Click on "Instructions" for details on how to use this tool. Click on "Explore" for more ideas. [Requires Java.]
Texas Instruments
Texas Instruments: Move Along Little Vertex
In this activity, students use the Geoboard to determine the area of triangles having the same base and same height.