Answer:
The border is 3 in wide along all edges of the table.
Step-by-step explanation:
You are told the total area is 3276 ft² and the dimensions of the table is 36 x 72 in
Either you really mean that the area is in in², or you have a huge border.
Presuming that the area is really in², adding in the border of "x" in makes the total length and width to be:
l = 72 + 2x
w = 36 + 2x
A = lw
3276= (72 + 2x)(36 + 2x)
3276 = 2592 + 216x + 4x²
subtracting 3276 from both sides:
4x² + 216x - 684 = 0
You would use the second of your four options to determine the length of the border.
Dividing both sides by 4:
x² + 54x - 171 = 0
completing the square:
x² + 54x = 171
x² + 54x + 729 = 171 + 729
(x + 27)² = 900
x + 27 = ± 30
x = -27 ± 30
Throwing out the negative number, our remaining x is:
x = 3
The border is 3 in wide along all edges of the table.
