CK12 - Geometry

The ratio betweenthe areasof the two figuresis the squareof the ratio of the linearmeasurement:

This relationshipholdsfor solidfiguresas well. The ratio of the areasof two similarfiguresis equalto the
squareof the ratio betweenthe correspondinglinearsides.

Example 3

Find the ratio of the surfacearea betweenthe two similarfiguresC and D.

Sincethe two figuresare similar, you can use the ratio betweenany two correspondingmeasurementsto
find the answer. Here,only the radiushas beensupplied,so:

The ratio betweenthe areasof the two figuresis the squareof the ratio of the linearmeasurements:

Example 4

If the surfacearea of the smallcylinderin the problemaboveis 80π, whatis the surfacearea of the larger
cylinder?

Fromabovewe, knowthat:

So the surfacearea can be foundby settingup equalratios

Solveforn.