OER Commons - Keywords: Triangles
https://www.oercommons.org
daily12000-01-01T12:00+00:00Eratosthenes Model
https://www.oercommons.org/courses/eratosthenes-model
The Eratosthenes model displays the shadows cast by two gnomons (sticks) at different locations on Earth. For one gnomon, Sun is directly overhead (as would be the case if the gnomon was on the Tropic of Cancer at the summer solstice). The other gnomon is due north of the first gnomon. The sizes of the gnomons are greatly exaggerated for visibility. This simulation can be used to help illustrate how Eratosthenes was able to measure the diameter of Earth using the shadows cast by two gnomons, one situated due north of the other, on a day when the southerly gnomon cast no shadow at all. The distance between the two gnomons (along Earth's surface) can be adjusted. The length of the shadow is given, and this length can be used to determine the angle between the gnomon lines and from that the circumference (and diameter, radius, etc) of Earth. Earth can be hidden to give a better view of the relevant geometry. Eratosthenes model is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Eratosthenes.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open EJS Model" from the pop-up menu item.Todd TimberlakeHistory, Law, PoliticsMathematicsComputing and InformationGeosciencePhysicsSpace ScienceEducation2015-04-08T18:13:31.106312Course Related MaterialsA Geometric Proof of the Pythagorean Theorem
https://www.oercommons.org/courses/a-geometric-proof-of-the-pythagorean-theorem
This animated PowerPoint presentation uses shearing and the invariance of the area of triangles with congruent bases and heights to show a step-by-step geometric proof of the Pythagorean Theorem.Don LinkMathematics2015-03-31T17:46:22.141992Course Related MaterialsOrdered Simple Plot
https://www.oercommons.org/courses/ordered-simple-plot-2
Plot ordered pairs on the graph, and they will be connected in the order that they are input. This enables you to decide how the pairs should be connected, rather than having the computer connect them from left to right.MathematicsComputing and InformationEngineeringEducation2014-11-05T10:08:55.512546Course Related MaterialsVenn Diagram Shape Sorter
https://www.oercommons.org/courses/venn-diagram-shape-sorter-2
Sort colored shapes into a Venn diagram based on various characteristics. Venn Diagram Shape Sorter is one of the Interactivate assessment explorers.MathematicsComputing and InformationEngineeringEducation2014-11-05T10:08:52.715014Course Related MaterialsBuilding a Sierpinski Pyramid
https://www.oercommons.org/courses/building-a-sierpinski-pyramid
The purpose of this lab is to enable students to compute the perimeter and area of equilateral triangles, and to make the connection between area of triangles (2-D) and the surface area of pyramids (3-D). Furthermore, a secondary purpose to this lab is to allow students to construct – with contributions from everyone – a piece of art full of mathematical meaning and implications (from geometry, algebra, and even calculus!)MathematicsPhysics2014-11-02T13:20:15.160935Course Related MaterialsDiscovering the Pythagorean Theorem
https://www.oercommons.org/courses/discovering-the-pythagorean-theorem
Students will use a variety of different size squares to form right triangles. After recording the lengths of the sides, students will square the values and look for the relationship.MathematicsComputing and InformationEducation2014-11-02T13:20:15.047730Course Related MaterialsWhere Is ??? In The Room?
https://www.oercommons.org/courses/where-is-in-the-room
This is a visual activity where students must visualize a shape and then identify it in the room. Students will learn to see how everyday objects are geometric and remember what they look like for the exam.Mathematics2014-11-02T13:20:11.497441Course Related MaterialsLesson 26: The Distance and Midpoint Formulas
https://www.oercommons.org/courses/lesson-26-the-distance-and-midpoint-formulas
The lesson begins by associating the distance between two points with the right triangle that may be formed by joining the points and extending horizontal and vertical lines through the points. This linking is generalized to derive the distance formula for any two points in the plane. The midpoint formula is then derived by taking the average of the coordinates of the two points. Using the distance formula, the equation for circle is derived and then examples follow for finding the equation of a given circle.MathematicsComputing and InformationPhysicsEducation2014-11-02T13:20:08.846540Course Related Materials"The Patterns in Thumb and Finger Marks," by Francis Galton, Phil. Trans. Royal Society (vol. 182), selected pages( page 5 )
https://www.oercommons.org/courses/the-patterns-in-thumb-and-finger-marks-by-francis-galton-phil-trans-royal-society-vol-182-selected-pages-page-5
Source Archive: University College, London Theme(s): Physical and Intellectual Measurement Francis GaltonDavid Micklos (Cold Spring Harbor Laboratory;DNA Learning Center X-AUDIENCE)Dolan DNA Learning Center (Cold Spring Harbor Laboratory;DNA Learning Center X-AUDIENCE)Elof Carlson (SUNY at Stony Brook;Biology Department X-AUDIENCE)Garland Allen (Washington University at St. Louis;Biology Department X-AUDIENCE)Jan Witkowski (Cold Spring Harbor Laboratory;Banbury Center X-AUDIENCE)Paul Lombardo (University of Virginia;Center for Biomedical Ethics X-AUDIENCE)Steven Selden (University of Maryland;Education Policy and Leadership Department X-AUDIENCE)History, Law, PoliticsMathematicsLife ScienceSocial Sciences2014-10-23T12:43:49.233140Course Related Materials