Answer :
Since rectangles ABCD and EFGH are similar, we can take the ratios of the corresponding sides of the rectangles
[tex]\frac{AB}{AD}=\frac{EH}{EF}[/tex][tex]\frac{8}{4}=\frac{k}{6}[/tex]cross multiplying
8 x 6 = 4 x k
48 = 4k
4k = 48
Divide both sides by 4
k = 48/4
k = 12