Three last questions on my geometry final please help

Here's the first

HS / HK  =  DY / DL

32 / 15  = DY   /  24       multiply both sides by 24

24 * 32  / 15   = DY

(8/5)*32   = DY  =  51.2

Here's the second

We can find the scale factor thusly :

JK / EF  =  11.2 / 28   =    2/5  =  .4

For the third....it's lengthy....I am going to show you how to find one vertex in the new figure.....I'll let you find the other three....if you get stuck...let me know

Let's call one vertex in the "before" figure -  (-4,3)  -     A

Here's the formula  to get A'

New vertex  =   [  vertex point -  dilation center ] * scale factor  +   dilation center

So we have 

A '  =   [ (-4, 3)  - (7 , - 2)  ]  * 2  +   ( -7, - 2)

A'  =  [ (-11, 5 ) ] *2   +  ( -7, -2)

A'  =  (-22, 10)  + ( -7, -2)

A'  =  (-29, 8)

Now...just apply the same procedure separately to the other 3 vertices of the "before" figure  to find the  "after" points