Interesting think. So sorry if you get it wrong
The coefficients of x4 is 9. It has factors of 1, 3, and 9. The constant is 4. It has factors of 1, 2, and 4.
The (positive and negative) ratios of the factors of the coefficient of the x4 and the constant 4 are the potential rational roots of the function.
The answers are:
1, -1, 3, -3, 9, -9, 1/2, -1/2, 3/2, -3/2, 3/4, -3/4, 9/2, -9/2, 9/4, -9/4
73 inches hope this helps
According to my calculations the answer is 69