I believe it is opposite angles.. as a rhombus has two pairs, which combined with their 2 pairs of equal segments gives you opposite angles that are equal
the largest rectangular area is actually a square.
so the side would be 400/4 = 100 feet
area of a square is S^2
100^2 = 10,000 square feet
Multiply 2nd equqation by -1 and add to first
5x+4y=22
<u>-3x-4y=-10 +</u>
2x+0y=12
2x=12
divide by 2
x=6
sub back
3x+4y=10
3(6)+4y=10
18+4y=10
minus 18 both sides
4y=-8
divide by 4
y=-2
(x,y)
(6,-2) is solution