[tex]\bf ~\hspace{5em} \textit{ratio relations of two similar shapes} \\[2em] \begin{array}{ccccllll} &\stackrel{ratio~of~the}{Sides}&\stackrel{ratio~of~the}{Areas}&\stackrel{ratio~of~the}{Volumes}\\ \cline{2-4}&\\ \cfrac{\textit{similar shape}}{\textit{similar shape}}&\cfrac{s}{s}&\cfrac{s^2}{s^2}&\cfrac{s^3}{s^3} \end{array} \\\\---------------------------------[/tex]
[tex]\bf \cfrac{\textit{similar shape}}{\textit{similar shape}}\qquad \cfrac{s}{s}=\cfrac{\sqrt{s^2}}{\sqrt{s^2}}=\cfrac{\sqrt[3]{s^3}}{\sqrt[3]{s^3}} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \cfrac{large}{small}\qquad \qquad \cfrac{side^2}{side^2}=\cfrac{area}{area}\implies \cfrac{4.5^2}{s^2}=\cfrac{18}{8}\implies \cfrac{4.5^2}{s^2}=\cfrac{9}{4}[/tex]
[tex]\bf \left( \cfrac{4.5}{s} \right)^2=\cfrac{3^2}{2^2}\implies \cfrac{4.5}{s}=\sqrt{\cfrac{3^2}{2^2}}\implies \cfrac{4.5}{s}=\cfrac{3}{2}\implies 9=3s \\\\\\ \cfrac{9}{3}=s\implies 3=s[/tex]
Answer:
The corresponding side is 3 cm
Step-by-step explanation:
When we have area, it is the related to the scale factor by the scale factor squared
Area large/ area of small = 18/8 = 9/4
Take the square root
sqrt(9/4) = 3/2
The scale factor is 3/2 large to small
The large side is 4.5 cm
large 3 4.5 cm
-------- = ------ = -----------
small 2 x cm
Using cross products
3x = 2(4.5)
3x =9
Divide each side by 3
3x/3 = 9/3
x =3
