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Slant Height

Christine — Wed, 18 Nov 2009 00:34:36 +0000

How to Find Slant Height

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Description

A detailed tutorial on how to find the slant height. Step by step tutorial including several examples of how to find the slant height for reference.

Overview

The slant height is an additional measure of height that is used for the different types of triangular prisms. The common traingular prisms are your typical pyramid, and cones. On a pyramid, the slant height is the height of one of the triangular faces. On a cone, the slant height is to be found using a formula that is only for the cone. It is the square root of the radius squared added to the real height squared.

Surface Area – Cones

Christine — Tue, 08 Sep 2009 19:00:37 +0000

How to Find the Surface Area of a Cone

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Description

This video gives a clear example on how to solve for the surface area of a cone. The formula is explained and a sample problem is solved in the video.

Overview

The surface area is the area of each side, or face, of the shape added together. Cones are a very tricky shape to calculate the surface area of, because there is something called a “slant height” that needs to be used. The formula for the surface area of a cone is:

SA = B + pi * r * l

B is the area of a base. The base of a cone is always a circle. r is the radius of the circle – the base. l is the slant height. Sometimes you are given the slant height, but not always. If the slant height is not given to you then you can use this formula to find it:

l = sqrt(r^2 + h^2)

h represents the regular height of the cone, as opposed to the slant height. This is actually the pythagorean theorem – you can form a right triangle with it if you draw a picture.

Volumes – Cones

Christine — Tue, 08 Sep 2009 17:01:13 +0000

How to Find the Volume of a Cone

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Description

This video gives an easy visual demonstration of the differences in volumes of two different shapes – a cone and a cylinder. The video proves that the formula must be different, because even though the height and base are exactly the same the volume is definitely not the same.

Overview

A cone is a pyramid that has the base shape of a cylinder instead of a rectangular prism. The volume of a cone can be expressed as:

V = (1/3) * B * h

Where h is the height, and B is the area of the base – the area of the base is the area of a circle, and can be expressed as pi * r^2.