The dimensions of the actual coin and the photo have all the same scale, therefore, the ratio must be the same. If we call the distance across the actual coin as x, we have:
[tex]\frac{8mm}{2cm}=\frac{x}{3.25cm}[/tex]Solving for x:
[tex]x=\frac{4mm}{cm}\times3.25cm=13mm[/tex]The actual distance across the coin is 13 mm.
