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Cross_sections_of_3D_objects

It's pretty difficult to work, mentally, with 3D objects. One way of overcoming that difficulty is in thinking about cross sections of such objects. These are 2D slices of 3D objects, and so we're back with the familiar 2D world.

Volume_of_rectangular_prisms

Welcome to the 3rd dimension! [cue spooky music] This tutorial explains how to find volume.

Surface_area

Learn how to find the total area of the surfaces of 3D shapes. To do this, we wrap 3D shapes in 2D nets.

Surface_and_volume_density

Use your knowledge of surface area and volume to solve problems involving density.

Solid_geometry

Tired of perimeter and area and now want to measure 3-D space-take-upness. Well you've found the right tutorial. Enjoy!

Heron_s_formula

Named after Heron of Alexandria, Heron's formula is a power (but often overlooked) method for finding the area of ANY triangle. In this tutorial we will explain how to use it and then prove it!

Volume_of_cones_cylinders_and_spheres

Let's see how to find the volumes of cylinders, spheres and other three dimensional shapes.

Koch_snowflake_fractal

Named after Helge von Koch, the Koch snowflake is one of the first fractals to be discovered. It is created by adding smaller and smaller equilateral bumps to an existing equilateral triangle. Quite amazingly, it produces a figure of infinite perimeter and finite area!

Volume_with_fractions

Finding the volume of rectangular prisms that have fractional side lengths

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