a circular garden has a diameter of 12 ft. how many bags of topsoil must linda buy to cover the garden if one bag covers and area of 3 sq ft? i know the answer is 38, but how do you arrive at that answer?
2007-06-14 04:33:00 · 5 answers · asked by pinkliner8 1 in Science & Mathematics ➔ Mathematics
The area of a circle is pi*(radius^2)
The radius is 1/2 of the diameter, and pi ~ 3.14159
Therefore we get the area of the garden to be:
A = 3.14159*( 6^2) ft^2
A = 113.1 ft^2
Since one bag covers 3ft^2, we can divide our area by this to get the number of bags.
113.1 / 3 = 37.7 bags
We need to round up because you can't by 0.7 bags at the store:
38 bags
2007-06-14 04:40:02 · answer #1 · answered by Math Stud 3 · 0⤊ 0⤋
First of all, you would need to find out the area of the garden. The equation for the area of the circle is pi * r * r, where r is the radius of the circle (the diameter divided by 2). This works out to be roughly 113.097. You the simply need to divide it by 3 to get the amount of bags you need. This works out to be 37.699 - then you simply need to round this up to get 38.
2007-06-14 11:40:29 · answer #2 · answered by Peter B. 2 · 0⤊ 0⤋
ok well the area of the circle is pi*r^2
so pi*6^2 which is about 113.04 sq ft
so if one bag covers 3 sq feet then do 113.04/3=37.68 and since she cant buy .68 of a bag you must round up to the next whole # so she has enough soil so thats how you get 38
2007-06-14 11:40:07 · answer #3 · answered by Lizzy G 2 · 0⤊ 0⤋
diameter=12 ft
radius=6 ft
area=pi*6^2=36*pi
# bags=36*pi/3=37.7 bags, 38 bags must be purchased to cover.
2007-06-14 11:40:24 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Area is Pi R squared. . So 6x6 (radius squared)x3.14 then divided by 3=37.68
or 38
2007-06-14 11:40:57 · answer #5 · answered by RB 7 · 0⤊ 0⤋