To cross-multiply, you typically need a proportion, which involves two fractions set equal to each other. If you have an equation like:
\[ \frac{a}{b} = \frac{c}{d} \]
then cross-multiplying means rearranging it to:
\[ a \cdot d = b \cdot c \]
However, from your message, I see you mention "Response area = 36" without any other context. It seems you're referencing a specific value, but I would need additional information or a specific fraction or equation to assist with cross-multiplication.
Could you please provide the complete equation or proportions you would like to work with?