Answer:
X = 48 inches for the shortest side
Explanation:
9s = first side
10s = second side
4s = third side
Perimeter = sum of the sides
276 = 9s + 10s + 4s
276 = 23s
276/23 = s
12 = s
9s = first side; 9(12) = 108
10s = second side; 10(12) = 120
4s = third side; 4(12) = 48