9:7=81:n
You asked:
Solve \(9 : 7=81 : n\) for the variable \(n\).
MathBot Answer:
$$\begin{aligned}n &= 63\end{aligned}$$
Express both ratios as fractions. \[\frac{9}{7} = \frac{81}{n}\]
Cross-multiply and solve for the unknown. $$\begin{aligned}\frac{9}{7} &= \frac{81}{n} \\ 9 n &= 567 \\ n &&= 63 \end{aligned}$$