Question 945562
It is easier to see if you graph them:
{{{drawing(300,300,-7,3,-3,7,grid(1),
blue(line(-5,4,-2,4)),blue(line(-2,4,-2,2)),blue(line(-5,2,-2,2)),blue(line(-5,4,-5,2)),locate(-5.3,4.5,A),locate(-1.9,4.5,B),locate(-1.9,2,C),locate(-5.3,2,D) )}}} and {{{drawing(300,300,-3,7,-8,2,grid(1),
green(line(-2,0,4,0)),green(line(4,0,4,-6)),green(line(-2,-6,4,-6)),green(line(-2,0,-2,-6)),locate(-2.3,0.5,E),locate(-2.3,-6,H),locate(4.1,0.5,F),locate(4.1,-6,G) )}}}
 
But even without drawing them, you could figure it out:
ABCD is a rectangle because
AB is a horizontal line because the y-coordinate for both points (A and B) is the same: 4.
CD is a horizontal line because the y-coordinate for both points (C and D) is the same: 2.
BC is a vertical line because the x-coordinate for both points (B and C) is the same: -2.
AD is a vertical line because the x-coordinate for both points (A and D) is the same: -5.
Sides AB and CD have {{{length=-2-(-5)=-2+5=3}}} .
Sides AD and BC have {{{length=4-2=2}}} .
So, ABCD is a rectangle whose sides are in the ratio 3:2.
 
To be similar, EFGH must be a rectangle,
and its side lengths must be in the same 3:2 ratio.
In the general meaning of the term rectangle, EFGH is a rectangle too, because
EF is a horizontal line because the y-coordinate for both points (E and F) is the same: 0.
GH is a horizontal line because the y-coordinate for both points (G and H) is the same: -6.
FG is a vertical line because the x-coordinate for both points (F and G) is the same: 4.
EH is a vertical line because the x-coordinate for both points (E and H) is the same: -2.
However,
sides EF and GH have {{{length=4-(-2)=4+2=6}}} , and
sides FG and EH have {{{length=0-(-6)=0+6=6}}} ,
So the side lengths are in a 1:1 ratio.
The rectangle EFGH is a square,
not at all similar to the rectangle ABCD.