www.numberpower.org Geometry Formulas When working with geometry always draw the figure, putting in the measurements. This habit helps when going over the homework without the book or checking for errors. Always write the formula ( abbreviations are okay). Plug in the numbers. Solve - being sure to add the measurement.
 Perimeter Think of it as the outside edge of a yard. You can also consider the perimeter as a fence. Perimeter is found by adding all the exterior edges (that is sides) of any polygon. Always write the formula: Perimeter = side 1 + side 2 + side 3 + side 4 + side 5 and so on. OR P = s 1 + s 2 + s3 + s 4 + s 5 and so on. Circles - Think of a pie - what shape do you see? A circle Therefore when working with any shape containing a circle you will use "pi" (pronounced pie). "pi" = 3.14 or 22/7 Circumference is like the perimeter - the part of a wheel that touches the ground. Circumference - "pi" x diameter Area is the inside of a pizza Area = "pi" x radius x radius Area – Think of it as the grass part of a yard or the wall. Area for a square or a rectangle if found by multiplying the length (base) by the width (height). The answer always has the word square after it. Always write the formula: Area = base X height OR A = b X h Area – Think of it as the grass part of a yard or the wall. Area for a square or a rectangle is found by multiplying the length (base) by the width (height). The answer always has the word square or a small 2 after the measurement. Always write the formula: Area = base X height OR A = b X h
 Perimeter Area Area - Find the Missing Side Circles