To find the surface area of a rectangular prism, we can use the formula:
\[ \text{Surface Area} = 2lw + 2lh + 2wh \]
where \( l \) is the length, \( w \) is the width, and \( h \) is the height.
In this case:
- Length (\( l \)) = 10 inches
- Width (\( w \)) = 9 inches
- Height (\( h \)) = 3 inches
Now, we can substitute these values into the formula:
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Calculate \( 2lw \): \[ 2lw = 2 \times 10 \times 9 = 180 , \text{square inches} \]
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Calculate \( 2lh \): \[ 2lh = 2 \times 10 \times 3 = 60 , \text{square inches} \]
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Calculate \( 2wh \): \[ 2wh = 2 \times 9 \times 3 = 54 , \text{square inches} \]
Now, sum these areas to find the total surface area:
\[ \text{Surface Area} = 180 + 60 + 54 = 294 , \text{square inches} \]
Thus, the surface area of the rectangular prism is \( \boxed{294} \) square inches.