Answer:
uniform width around the landing pad = 9.41 feet
Step-by-step explanation:
Length of landing pad = 80 ft
width of landing pad = 50 ft
Length of safety zone = (80 + 2w)
width of safety zone = (50 + 2w)
Total area = 10800 [tex]ft^{2}[/tex]
Area of landing pad = length x width
= 80 x 50
= 4000 [tex]ft^{2}[/tex]
Area of landing pad = 4000 [tex]ft^{2}[/tex]
Thus,
area of safety zone = total area - area of landing pad
= 10800 - 4000
= 6800
area of safety zone = 6800 [tex]ft^{2}[/tex]
But,
area of safety zone = length x width
6800 = (80 + 2w) x (50 + 2w)
6800 = 4000 + 160w + 100w + 4[tex]w^{2}[/tex]
divide through by 4,
1700 = [tex]w^{2}[/tex] + 65w + 1000
⇒ [tex]w^{2}[/tex] + 65w + 1000 - 1700 = 0
[tex]w^{2}[/tex] + 65w -700 = 0
Applying the quadratic formula,
w = (-b ± [tex]\sqrt{b^{2} -4ac}[/tex]) ÷ 2a
a = 1, b= 65 and c = -700
w = (-65 ± [tex]\sqrt{(65)^{2}-(4*1*-700) }[/tex]) ÷ 2
= (-65 ± [tex]\sqrt{7025}[/tex]) ÷ 2
= (-65 ± 83.82)÷ 2
w = (-65 + 83.82) ÷ 2 OR (-65 - 83.82) ÷ 2
= 18.82 ÷ 2 OR -148.82 ÷ 2
= 9.41 OR -74.41
Thus, w = 9.41 ft.
