Because 0.09 is ten times as big as 0.009
The answer is 9. 5625 / 625 = 9
This means that 5625 square feet of lawn would provide the daily supplies of oxygen for 9 people
A = 2lw + 2lh + 2wh
A = 2(43)(19) + 2(43)(35) + 2(19)(35)
A = 2(817) + 2(1505) + 2(665)
A = 1634 + 3010 + 1330
A = 5974in²
We know the perimeter formula would be 1200=2x+2y. And the area will be A=x*y
We can to take the derivative of the area formula to find where it is a max but we must first substitute something in from the first formula so we only have one variable.
1200-2x=2y
600-x=y
A=(x)*(600-x)
A=600x-x^2
Now we take the derivative:
A'=600-2x (set equal to 0 and solve)
0=600-2x
2x=600
x=300
Then when we plug this into the perimeter formula, we can solve for y
1200=2x+2y
1200=2(300)+2y
1200=600+2y
600=2y
y=300
So both the length and width are 300 yards, and the area would be 90,000 square yards
Hope this helps
