Reducing scale

I am sizing some landscaping, and I measured everything on a 20 to 1 scale. I realized when I was done that it was at 30 to 1. How can I convert what I already have to 30 to 1. (Example, if the grass area is 22,871.6' at 20 to 1, how do you figure it out to be 30 to 1?

Correct answer:

k =  0.6667

Step-by-step explanation:

$$\begin{gathered} k=\frac{20}{30}=\frac{2}{3}\doteq 0.6667 \\ A=228716 \\ B=k\cdot A=\frac{2}{3}\cdot 228716=\frac{2\cdot 228716}{3}=\frac{457432}{3}\doteq 152477.3333 \\ k=\frac{2}{3}=0.6667 \end{gathered}$$

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