Geometry For Dummies
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Geometric shapes have algebraic formulas for determining perimeter, area, surface area, and volume. The letters in the formulas stand for length, width, side, base, height, diameter, and radius:

l: length

w: width

s: side

b: base

h: height

d: diameter

r: radius

In this list, the shape is followed by two formulas, the first formula is for the perimeter (P) or circumference (C), and the second formula is for the area (A):

Rectangle:

P = 2(l + w) = 2l + 2w

A = lw

Square:

P = 4s

A = s2

Triangle:

P = s1 + s2 + s3

A = 12bh

Trapezoid:

P = s1 + s2 + s3 + s4

A = 12h(b1 + b2)

Parallelogram:

P = 2(b + s) = 2b + 2s

A = bh

Circle:

image0.png

In this list, the shape is followed by two formulas, the first formula is for the surface area (SA), and the second formula is for the volume (V):

Rectangular prism (box):

SA = 2lw + 2lh + 2wh

V = lwh

Cylinder:

image1.png

Sphere:

image2.png

About This Article

This article is from the book:

About the book author:

Mark Ryan has taught pre-algebra through calculus for more than 25 years. In 1997, he founded The Math Center in Winnetka, Illinois, where he teaches junior high and high school mathematics courses and standardized test prep classes. He also does extensive one-on-one tutoring. He is a member of the Authors Guild and the National Council of Teachers of Mathematics. Ryan is the author of Calculus For Dummies, Calculus Workbook For Dummies, and Geometry Workbook For Dummies.

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