One property of the diagonals of a rhombus is that they are perpendicular bisectors of each other. So 4 congruent right triangles will be formed when you draw the two diagonals. Considering one right triangle, we can solve for the two sides by dividing them by 2.
24 ft/ 2 = 12 ft
18 ft/ 2 = 9 ft
Using the Pythagorean Theorem, we can now solve for the hypotenuse which is the side of the rhombus.
side = √(12²+9²) = 15 ft
The answer is B.
