Education.com
Try
Brainzy
Try
Plus

The Perimeter of Noncircular Shapes Study Guide

By
Updated on Oct 3, 2011

Introduction to The Perimeter of Noncircular Shapes

With me everything turns into mathematics.

—Renè Descartes (1596–1650)

This lesson will describe ways that geometry is used for measuring, specifically perimeter. Perimeter has many uses in real life outside of your math classroom.

When you measure the distance around a noncircular shape, you are finding its perimeter.

Perimeter

Perimeter is an addition concept; it is a linear, one-dimensional measurement.

To find the perimeter of a noncircular shape, add up all of the lengths of the sides of the figure. Be sure to name the units.

The perimeter of a square, or any rhombus, is equal to 4s, where s is the length of a side. Because all four sides are equal, when you measure the distance around a square, you get s + s + s + s, or 4s.

Perimeter

In a rectangle, like all parallelograms, the opposite sides are parallel and congruent. The perimeter of a rectangle is 2l + 2w, where l equals the length and w equals the width. Always remember that the length is longer.

Perimeter

To find the perimeter of a triangle, you just add up the lengths of all three sides:

Perimeter

Let's practice!

Find the perimeter of a square whose side is 5 cm.

You know that each side of a square is equal. So, if you know that one side of a square is 5 cm, then you know that each side of the square is 5 cm. To calculate the perimeter, add up the lengths of all four sides.

    5 + 5 + 5 + 5 = 20

So, the perimeter of a square whose side measures 5 cm is 20 cm.

Tip:

Be alert when you work with geometry problems to make sure that the units are consistent. If they are different, you must make a conversion before calculating perimeter or area.

Find practice problems and solutions at The Perimeter of Noncircular Shapes Practice Questions.

Add your own comment

Ask a Question

Have questions about this article or topic? Ask
Ask
150 Characters allowed