Given figure ABCD ~ figure WXYZ, what is the value of k?

---- m

http://static.k12.com/calms_media/media/1572000_1572500/1572062/1/91e95b6c5fdd03787002cc188acb432ee1656255/MS_IMC-141210-110201.jpg

Question

Given figure ABCD ~ figure WXYZ, what is the value of k? 
 
 ---- m

http://static.k12.com/calms_media/media/1572000_1572500/1572062/1/91e95b6c5fdd03787002cc188acb432ee1656255/MS_IMC-141210-110201.jpg

anonymous · Answer

The shapes are similar, so in that case, if line CB is 4.2, and line YX is 8.4, that means in was doubled in size. So do the same to k. Line DC is 2.3. What is 2.3 doubled?

anonymous · Answer

4.6 sorry i took so long

anonymous · Answer

Yes!!! Good job. So line ZY = 4.6! You did it! :)

anonymous · Answer

thanks! :)