- The quadrilateralsin the upperleft arenotsimilarbecausethey are not the sameshape.
- The quadrilateralsin the upperrightaresimilar. Theyare all the sameshape,no matterwhattheir sizes.
- The quadrilateralsin the lowerleftaresimilar. Theyare all the sameshape,no matterhow they are
turnedor whattheir sizes.
Now let’s get seriousaboutwhatit meansfor figuresto be similar. The rectanglesbelowareall similarto
eachother.
Theserectanglesare similar, but it’s not just becausethey’rerectangles.Beingrectanglesguaranteesthat
thesefiguresall havecongruentangles.But that’s not enough.You’veseenlots of rectanglesbefore,some
are long and narrow, othersare moreblockyand closerto squarein shape.
The rectanglesaboveare all the sameshape.To convinceyourselfof this you couldmeasurethe length
and widthof eachrectangle.Eachrectanglehas a lengththat is exactlytwiceits width.So the ratio of length-
to-widthis for eachrectangle.Now we can makea moreformalstatementof whatsimilarmeansin
geometry.