Answer: a) 21 cans
b) 10.83 square inches.
Step-by-step explanation:
The cans are cylinders of 4 and 1/4 inches tall (or 4.25 in)
and the diameter is 3 inches.
The surface of a cylinder is equal to:
S = pi*r^2 + h*2*pi*r
where r is the radius, half of the diameter, so we have that r = 3in/2 = 1.5 in.
h is the height, h = 4.25 in
pi = 3.14
Then the surface needed for a can is:
S = 3.14*1.5^2 + 4.25*2*3.14*1.5 = 47.1 square inches.
if the sheet is 1000 in^2, we can make an amount of:
N = 1000/47.1 = 21.23
but we can not do a 0.23 of a can, so we need to round down.
A) we can make 21 cans out of a sheet of metal.
B) the 0.23 of a can that we removed earlier is the amount of metal leftover. The total is 0.23*47.1 in^2 = 10.83 in^2
