Formulas of Geometry

You will use a number of geometric formulas as you work through your algebra book. Here are some perimeter, area, and volume formulas.

A rectangle has length l and width w. P, or perimeter, = 2l + 2w. A or area = l times w

Rectangle

A square has sides with length s. P = 4s. A = s squared.

Square

A circle has diameter d and radius r. Circumference C = 2 pi r or C = pi d.

Circle

A triangle has a base and height. The height is measured at a right angle from the base to the angle opposite the base.

Triangle

A parallelogram has a base and height. The height is measured at a right angle to the base. The area A = b times h.

Parallelogram

A trapezoid has 2 bases: b subscript 1 baseline and b subscript 2 baseline. It also has height. The height is measures at a right angle to the bases. The area A = one-half (b subscript 1 baseline + b subscript 2 baseline) times height.

Trapezoid

A rectangular prism has length l, width w, and height h. The volume V = B (the area of the base) times height. Or V = l times w times h.

Right Prism

A pyramid has a square base and height. The height is measured to the peak at a right angle to the base. The volume V = one-third B (the area of the base) times h.

Pyramid

A right circular cylinder has a base and height. The base has radius r. The volume V = Bh or V = pi r squared h

Right Cylinder

A right circular cone has a base with radius r and height. The height is measured at a right angle from the base to the peak. The volume V = one-third B (the area of the base) h or V = one-third pi r squared h.

Right Cone

A sphere has radius r. The volume = one-third pi r cubed.

Sphere


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Table of Contents

Prentice Hall Algebra 1 Chapter 1 Foundations for Algebra Chapter 2 Solving Equations Chapter 3 Solving Inequalities Chapter 4 An Introduction to Functions Chapter 5 Linear Functions Chapter 6 Systems of Equations and Inequalities Chapter 7 Exponents and Exponential Functions Chapter 8 Polynomials and Factoring Chapter 9 Quadratic Functions and Equations Chapter 10 Radical Expressions and Equations Chapter 11 Rational Expressions and Functions Chapter 12 Data Analysis and Probability Skills Handbook Reference Visual Glossary Selected Answers Index Acknowledgments