Question

The net for a cylindrical candy container is shown.

net of a cylinder with diameter of both circles labeled 1.6 inches and a rectangle with a height labeled 0.7 inches

The container was covered in plastic wrap during manufacturing. How many square inches of plastic wrap were used to wrap the container? Write the answer in terms of π.

1.84π square inches
2.4π square inches
5.68π square inches
6.24π square inches

Answer 1

Answer: The real answer is 2.4π square inches (B)

Explanation:

(Get ready for a long explanation)

So, we are trying to find the Surface Area of the cylinder.

We need to use the formula (SA = 2πr^2 + 2πrh)

Looks like a very long formula, but let do it in parts.

So the first part is just finding the area of the circle and multiplying by 2 because there are two bases. The area formula for circles is (πr^2)

But this time put a 2 in there. (2πr^2)

Okay lets get started. The diameter is 1.6. The radius is half the diameter, so divide 1.6 by 2 and you will get 0.8 which is the radius.

Now times the radius by itself (0.8 * 0.8 = 0.64) Now times that by 2 (0.64 * 2 = 1.28) The answer should be in terms of pi so just put the pi symbol next to 1.28 (1.28π)

On to the next part, (2πrh) you are basically taking the circumference of either circle base, and multiplying that by the height, which is (0.7)

The formula for Circumference is (2πr)

We already have the diameter so we don't need times the radius by 2.

So take the diameter of the circle base (1.6) and multiply that by the height, which is (0.7)
(1.6 * 0.7 = 1.12π)

Now for the last part, we need to add the two values together to find the surface area.

The first value we found is (1.28π ) and the second is (1.12π)

Now add (1.28π + 1.12π = 2.4π)

Answer: 2.4π square inches

Sorry for the really long explanation. I took the same test and I got it right so here is proof that it is correct. Have a great day y'all.