Answer:
H.) 7,2,5
Explanation:
You want to know which set of lengths could not be used as the sides of a triangle.
Triangle inequality
The triangle inequality requires the sum of the two shorter sides of a triangle exceed the length of the longer side;
F. 5 + 8 > 9 . . . can be used
G. 4 + 6 > 8 . . . can be used
H. 2 + 5 = 7 . . . cannot be used for the walkway
J. 7 + 8 > 9 . . . can be used
The lengths 2, 5, 7 cannot be used to form a triangle.
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Additional comment
Such a "triangular walkway" (2, 5, 7) would look like a single walk, 7 feet long. The "triangle" would have no area.