Useful diagrams. Click to open the Word file: 3d-diagrams

# Category Archive: geometry

Oct 06

## Archimedes’ Puzzle

http://illuminations.nctm.org/Lesson.aspx?id=2523 “The Stomachion is an ancient tangram-type puzzle. Believed by some to have been created by Archimedes, it consists of 14 pieces cut from a square. The pieces can be rearranged to form other interesting shapes. In this lesson, students learn about the history of the Stomachion, use the pieces to create other figures, learn about …

Apr 27

## Conic Sections on Desmos

Go to this Desmos graph https://www.desmos.com/calculator/tsfynm2to8 It shows two each of the four conic sections Circles, Ellipses, Hyperbolas, Parabolas Note: A hyperbola has two branches. Only one is shown in the image. A cone actually has two frustums. The image only shows one frustum. http://www.intmath.com/plane-analytic-geometry/conic-sections-summary-interactive.php

Apr 20

## Why the Area of a Trapezoid is What it is

There are six ways to show that the area of a trapezoid is See the following PowerPoint file:TrapezoidArea6Ways

Mar 23

## Spotting Numbers and Visual Patterns

Here a two great websites that provide lots of great pattern problems. Spotting Numbers – interactive, does require Java. Visual Patterns – less interactive, (no Java needed). These patterns can be used with elementary students (if you just ask number questions) through advanced algebra (if you include questions about functions). Mathematics is often described as …