What is "if the length of fh is 18 units?

If the length of segment FH is 18 units, it means that the distance between point F and point H is 18 units. This information can be used to calculate various geometric properties of the figure in which FH is a part of. For example, if FH is a side of a triangle, knowing its length can help determine the area, perimeter, and angles of the triangle. Similarly, if FH is a side of a square or rectangle, its length can help determine the perimeter and area of the shape. Having the length of FH allows for more precise and accurate calculations in geometry problems and can provide valuable information about the given figure.