porportion

Let $x$ = price of $2\frac{1}{2}$ yards of fabric

$\frac{6\frac{1}{4}}{25.5}=\frac{2\frac{1}{2}}{x}$

$\frac{\frac{25}{4}}{\frac{51}{2}}=\frac{\frac{5}{2}}{x}$

$\frac{25}{4}\times\frac{2}{51}=\frac{5}{2}\times\frac{1}{x}$

$\frac{50}{204}=\frac{5}{2x}$

$50\times2x=204\times5$

$100x=1020$

$x=10.2$

$2\frac{1}{2}$ yards of fabric will cost $$10.20$ when $6\frac{1}{4}$ yards of fabric costs $$25.50.$