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Please help me understand this!Problem:The net of a rectangular prism and it's dimensions are shown in the diagram.Question:What is the total surface area of the rectangular prism in square inches?A. 143.25 in.^2B. 241.5 in.^2C. 258.75 in.^2D. 286.5 in.^2

Please help me understand this!Problem:The net of a rectangular prism and it's dimensions-example-1
User Encubos
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1 Answer

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Surface Area

The image shows the shape of a rectangular prism

The surface area of the shape is the sum of all the individual rectangles

There are 6 small rectangles. We'll find their area and add them up to find the total surface area.

The area of a rectangle of dimension L and W is:

A=L.W

First rectangle: 3 in x 7.5 in

A1 = 3 * 7.5 = 22.5 square inch

Second rectangle: 11.5 in x 3 in

A2 = 3 * 11.5 = 34.5 square inch

Note this rectangle is repeated twice

The third rectangle has the same area of the first rectangle:

A3 = 3 * 7.5 = 22.5 square inch

The fourth rectangle has dimensions of 7.5 x 11.5

A4 = 7.5 * 11.5 = 86.25 square inch

This rectangle is also repeated twice

The total area is :

A = A1 + A2 + A2 + A3 + A4 + A4

A = 22.5 + 34.5 + 34.5 + 22.5 + 86.25 + 86.25

A = 286.5 square inch

Answer: D.

User Celsomtrindade
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