Pre-Algebra Essentials For Dummies

Chapter 11

Geometry: Perimeter, Area, Surface Area, and Volume

IN THIS CHAPTER

Examining two-dimensional shapes

Looking at solid geometry

Finding out how to measure a variety of shapes

Geometry is the mathematics of figures such as squares, circles, triangles, lines, and so forth. Because geometry is the math of physical space, it’s one of the most useful areas of math. Geometry comes into play when measuring rooms or walls in your house, the area of a circular garden, the volume of water in a pool, or the shortest distance across a rectangular field.

In this chapter, I give you the basics on geometric shapes, from flat circles to solid cubes. Then I discuss how to measure geometric shapes by finding the area and perimeter of two-dimensional forms and the volume and surface area of some geometric solids.

Closed Encounters: Understanding 2-D Shapes

Plane geometry is the study of figures on a two-dimensional (2-D) surface — that is, on a plane. You can think of the plane as a piece of paper with no thickness at all. Technically, a plane doesn’t end at the edge of the paper — it continues ...