Question

In a roll of aluminum foil, the inner cardboard tube has a diameter of 1.75 inches and a height of 18 inches I the tube is cut and unfolded to form a rectangle, what is the lateral area?​

Answer 1

The "width" of the rectangle would be the "circumference" of the tube whereas the length is merely the height of the tube.
.
Therefore, we have:
length = 11 inches
width = 2(pi)r = 2(3.14)(1.7) = 2(3.14)(1.7/2)
width = (3.14)(1.7)
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area of rectangle = length * width
area of rectangle = 11(3.14)(1.7) = 58.718 square inches