Curated OER
NON-EUCLIDEAN GEOMETRY.
Students study relationships between angles, side lengths, perimeters, areas and volumes of similar objects. In this lesson students also create and critique inductive and deductive arguments concerning congruency, similarity and the...
Curated OER
Math: Equal Area Triangles
Students examine a math worksheet and determine how to divide a single triangle into four of equal area. Using geometric principles, they sketch two additional ways to divide into into four equal triangles. To conclude, students...
Curated OER
THE MEAN INDEX CARD
Middle schoolers cut an index card to create three similar right triangles and explore the congruencies and proportions that exist. They investigate the properties of lines and concepts of congruency, similarity, tangency and symmetry of...
Curated OER
Interactivate - Lines, Rays, Line Segments, and Planes
Students explore lines, rays, line segments, and planes. In this math lesson, students discuss the math concepts and direct their instructor in graphing functions. Students collaborate in graphing additional functions.
Shodor Education Foundation
Surface Area of Rectangular Prism
With this interactive instructional activity, learners compute the surface area of rectangular prisms. They visit an online investigation applet and record data on the provided handout. Pair this instructional activity with the volume...
Shodor Education Foundation
Volume of Prisms
Explore the concept of volume of prisms using an applet to perform the calculations. The link to the interactive applet is embedded into the lesson plan as well as a link to associated data sheets. Get your math class to the computer lab...
Curated OER
Volume of Rectangular Prisms
Introduce the procedure needed to find the volume of a rectangular prism. Learners rank various prisms such as cereal boxes and tissue boxes from smallest to largest volume. They use an applet to find the volume and surface area of each...
Curated OER
Probability and Geometry
Students practice calculating probability, see how geometry can help solve probability problems and explore platonic solids.
Curated OER
Surface Area of Prisms
Students compute surface area and volume of prisms. In this surface area lesson plan, students find the surface area and volume of rectangular and triangular prisms. Independently, students use their computers to determine the volume,...
Curated OER
Parallel-o-Home
Students investigate the usage of parallel and perpendicular shapes in the real world. In this geometry lesson, students investigate shapes for properties that are related to the real world. They relate all the properties of shape tot he...
Curated OER
Congruent Triangles Postulates
Students discover three lettered postulates that prove triangles congruent.
Curated OER
Lines, Rays, Line Segments, and Planes
Students are introduced to lines, rays, line segments and planes and study the differences between them. They also practice graphing lines, rays, line segments and planes
Maths Challenge
Maths challenge.net: Equal Angles
A geometric proof. Prove two angles in this model are equal in measure.
Maths Challenge
Maths challenge.net: Tri Angles
A geometry proof involving exterior angles of a triangle.
Shodor Education Foundation
Shodor Interactivate: Squaring the Triangle
Learn about how the Pythagorean Theorem works through investigating the standard geometric proof.
Other
Propagation of Light Using Geometry
A discussion of Christian Huygens' contribution to wave optics, and particularly to our understanding of the reflection and refraction of light. Excellent diagrams and a geometric proof on why the law of reflection is mathematically...
Maths Challenge
Maths challenge.net: Right Triangle Equal Parts
A geometry proof problem involving a right triangle and finding angles of equal measure.
Maths Challenge
Maths challenge.net: Unique Circle Equal Angles
A "three star geometry problem" - requiring the knowledge of biconditional statements and how to prove such problems.
Other
Antonio Gutierrez: Geometry From the Land of the Incas
Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...
National Council of Teachers of Mathematics
The Math Forum: Paper Folding Activity
This is a lesson plan of paper folding as a method of proof. A Java applet version of the activity can be accessed, giving the actual lengths and angle sizes.
Wolfram Research
Wolfram Math World: Rectangle
MathWorld provides the definition of a rectangle and the area formula of a rectangle.
Illustrative Mathematics
Illustrative Mathematics: G C Locating Warehouse
You have been asked to place a warehouse so that it is an equal distance from three roads on a map. Students must fold a paper so that this point is where two folds intersect, and they must explain why their construction works and why...