This is obviousbecausecongruentfigureshavethe sameamountof spaceinsidethem.However, two figures
with the samearea are not necessarilycongruent.
Areaof Wholeis Sumof PartsIf a figureis composedof two or morepartsthat do not
overlapeachother, then the area of the figureis the sum of the areasof the parts.This is the familiaridea that a wholeis the sum of its parts.In practicalproblemsyou may find it helpfulto
breaka figuredowninto parts.
Example 2
Find the area of the figurebelow.Luckily, you don’thaveto learna specialformulafor an irregularpentagon,whichthis figureis. Instead,
you can breakthe figuredowninto a trapezoidand a triangle,and use the area formulasfor thosefigures.
BasicAreaFormulas
Lookbackat Example1 and the way it was filled with unit area squares.
Noticethat the dimensionsare: