Answer:
FG = 16
Explanation:
the angle between EF ( y- axis) and EH (x- axis) is right
thus the 4 angles in EFGH are right angles meaning the figure is a square.
the sides of a square are congruent , so
GH = FG , that is
3x + 1 = x + 11 ( subtract x from both sides )
2x + 1 = 11 ( subtract 1 from both sides )
2x = 10 ( divide both sides by 2 )
x = 5
Then
FG = x + 11 = 5 + 11 = 16