Answer: C
\(a: \cfrac{27}{64}=\cfrac{3}{4}:a\)
or, \(\cfrac{a}{\cfrac{27}{64}}=\cfrac{\cfrac{3}{4}}{a}\)
or, \(a^2=\cfrac{3}{4}\times \cfrac{27}{64}\)
or, \(a=\sqrt{\cfrac{81}{256}}\)
or, \(a=\cfrac{9}{16}\)
\(a: \cfrac{27}{64}=\cfrac{3}{4}:a\)
or, \(\cfrac{a}{\cfrac{27}{64}}=\cfrac{\cfrac{3}{4}}{a}\)
or, \(a^2=\cfrac{3}{4}\times \cfrac{27}{64}\)
or, \(a=\sqrt{\cfrac{81}{256}}\)
or, \(a=\cfrac{9}{16}\)