Huong covered a box with sticky-backed decorating paper. The paper costs $.03 per square inch. How much money will Huong need to spend on paper if the length is 7 inches, width is 3 inches, and the height is 9 inches?

I thought Huong needed to spend $3.42 because I multiplied 0.3x9 and got .27, 0.3x3 and got .09, and 0.3x7 and got .21. Then I added .27, .09, and .21 and got .57 then I multiplied .57x6 (due to the number of sides) and got 3.42. If I am incorrect please help me on how to solve this problem, if I am correct please let me know. Thank you.

Your approach is correct, but there is a small calculation error in your solution. Let's go through the calculation again step by step.

The box has 6 sides in total (top, bottom, front, back, left, right). To find the area of each side, you need to multiply the length by the width.

Area of the top and bottom sides = (length x width) = (7 inches x 3 inches) = 21 square inches.

Area of the front and back sides = (length x height) = (7 inches x 9 inches) = 63 square inches.

Area of the left and right sides = (width x height) = (3 inches x 9 inches) = 27 square inches.

Now, you have the area of each side of the box. To find the total area, you need to add up the areas of all six sides.

Total area = (2 x top and bottom) + (2 x front and back) + (2 x left and right)
= (2 x 21 square inches) + (2 x 63 square inches) + (2 x 27 square inches)
= 42 square inches + 126 square inches + 54 square inches
= 222 square inches.

Since the paper costs $0.03 per square inch, you can now calculate the total cost by multiplying the total area by the cost per square inch.

Total cost = (Total area) x (Cost per square inch)
= 222 square inches x $0.03/square inch
= $6.66.

Therefore, Huong will need to spend $6.66 on paper to cover the box.

Your approach to solving the problem is partly correct, but there seems to be a slight calculation error. Let me guide you through the correct steps to solve this problem.

To calculate the total cost of the sticky-backed decorating paper, we need to find the surface area of the box, which will then be multiplied by the cost per square inch.

1. Calculate the surface area of each side of the box:
- One side has a length of 7 inches and a width of 9 inches, so its area is 7 * 9 = 63 square inches.
- Another side has the same dimensions, so its area is also 63 square inches.
- The remaining two sides have lengths of 3 inches and 9 inches, so each side has an area of 3 * 9 = 27 square inches.

2. Calculate the area of the other remaining two sides:
- Both sides have a length of 3 inches and a width of 7 inches, so each side has an area of 3 * 7 = 21 square inches.

3. Calculate the total surface area of the box by adding up the areas of all six sides:
- Total surface area = 2 * (63 square inches) + 2 * (27 square inches) + 2 * (21 square inches)
- Total surface area = 126 + 54 + 42 = 222 square inches.

4. Multiply the total surface area by the cost per square inch to find the total cost:
- Total cost = 222 square inches * $0.03 per square inch
- Total cost = $6.66.

Therefore, Huong will need to spend $6.66 on the sticky-backed decorating paper to cover the entire box.

there are three pairs of matching sides

two are L x W ___ 2 * 7 * 3

two are L x H ___ 2 * 7 * 9

two are W x H ___ 2 * 3 * 9

find the areas, add them together
multiply by the paper cost

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