How To Measure Triangles

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HomeAcademics & The Arts ArticlesMath ArticlesBasic Math ArticlesHow to Measure TrianglesByMark Zegarelli Updated2016-04-25 19:47:03From the bookBasic Math & Pre-Algebra For DummiesShare

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Download E-BookBasic Math & Pre-Algebra For Dummies Explore Book Fractions For Dummies Explore BookBuy NowBuy on AmazonBuy on WileySubscribe on PerlegoDownload E-BookBasic Math & Pre-Algebra For DummiesExplore Book Fractions For DummiesExplore BookBuy NowBuy on AmazonBuy on WileySubscribe on PerlegoYou can measure the perimeter and area of all triangles. There also is a special feature of right triangles that allows you to measure them more easily.

Finding the perimeter and area of a triangle

Mathematicians have no special formula for finding the perimeter of a triangle — they just add up the lengths of the sides.

To find the area of a triangle, you need to know the length of one side — the base (b for short) — and the height(h). Note that theheight forms a right angle with the base. This figure shows a triangle with a base of 5 cm and a height of 2 cm:

Here's the formula for the area of a triangle:

So here's how to figure out the area of a triangle with a base of 5 cm and a height of 2 cm:

Finding the third side of a right triangle

The long side of a right triangle (c) is called the hypotenuse, and the two short sides (a and b) are called the legs:

The most important right triangle formula is the Pythagorean theorem:

This formula allows you to find the hypotenuse of a triangle, given only the lengths of the legs. For example, suppose the legs of a triangle are 3 and 4 units. Here's how to use the Pythagorean theorem to find the length of the hypotenuse:

So when you multiply c by itself, the result is 25. Therefore, take the square root of both sides to find:

c = 5

The length of the hypotenuse is 5 units.

About This Article

This article is from the book: 

Basic Math & Pre-Algebra For Dummies

About the book author:

Mark Zegarelli is a math tutor and author of several books, including Basic Math & Pre-Algebra For Dummies.

This article can be found in the category: 

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