If square HIJK has a perimeter of 30 units, it means that each side measures 7.5 units.
[tex]l=\frac{30}{4}=7.5[/tex]For the square UVWT, each side would be 4.5 units long.
[tex]l=\frac{18}{4}=4.5[/tex]Then, we divide these magnitudes.
[tex]\frac{7.5}{4.5}=\frac{\frac{15}{2}}{\frac{9}{2}}=\frac{15\cdot2}{9\cdot2}=\frac{5}{3}[/tex]