$Length_B=\frac{3}{4}\times Length_A=\frac{3}{4}\times 64$

$Width_B=\frac{3}{4}\times Width_A=\frac{3}{4}\times 48$

$Length_C=\frac{3}{4}\times Length_B=\frac{3}{4}\times\frac{3}{4}\times 64=36$

$Width_C=\frac{3}{4}\times Width_B=\frac{3}{4}\times \frac{3}{4}\times 48=27$

$\therefore Perimeter_C=2\times(Length_C+Width_C)=2\times(37+26)=126$