Tara plans to put wallpaper on the walls of her room. She will not put the wallpaper across the doorway, which is 3 feet wide and 7 feet tall.

Find the expression which represents the number of square feet of wallpaper she will need if the height of her room is x feet, with a length and width that are each 3 times the height of the room. Assume that the walls are four rectangles.

Tara will need ___ square feet of wallpaper for her bedroom.

Question

Mathematics

Pandora

20 April, 16:26

Tara plans to put wallpaper on the walls of her room. She will not put the wallpaper across the doorway, which is 3 feet wide and 7 feet tall.

Find the expression which represents the number of square feet of wallpaper she will need if the height of her room is x feet, with a length and width that are each 3 times the height of the room. Assume that the walls are four rectangles.

Tara will need ___ square feet of wallpaper for her bedroom.

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Answers (1)

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Clancy · Answer 1

First,

To calculate the total Area we need to add the area of every wall (4 of them) and subtract the area of the doorway.

Height of the room ... x feet

Width ... 3x feet

Length ... 3x feet

As the width and length are the same, this means that

Area wall 1 = Area wall 2 = Area wall 3 = Area wall 4 = 3x*x = 3x²

A total = 3x² + 3x² + 3x² + 3x² - (7 feet*3 feet)

A total = 12x² - 21 feet²