To find the length of side B in inches using the conversion factor provided (1 centimeter = 3 inches), Guina needs to set up a proportion that relates the centimeters to inches.
Since side B is 3 centimeters in the drawing, we want to convert that to inches. We can express this as follows:
- The equivalent in inches can be found using the ratio \( \frac{1 \text{ cm}}{3 \text{ inches}} \).
To set up the proportion where 3 centimeters corresponds to \( x \) inches, the correct proportion would be:
\[ \frac{1 \text{ cm}}{3 \text{ inches}} = \frac{3 \text{ cm}}{x \text{ inches}} \]
This matches the third option in your list:
StartFraction 1 centimeters over 3 inches EndFraction = StartFraction 3 centimeters over x inches EndFraction.
This proportion can now be solved to find \( x \), which will give you the length of side B in inches.