Carpentry & Building Construction © 2004

Perimeter of a Rectangle

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A rectangle is a polygon with four right angles and four sides. The opposite sides of a rectangle are equal to each other. (Note the strokes on the drawing-they indicate equal lines.) The perimeter of a rectangle is the sum of the lengths for all the sides. In other words, it is the distance around the figure. Carpenters use knowledge about the perimeter of rectangles to figure how much lumber is needed for a job.

To find the perimeter of a rectangle, add the distances of the two sets of equal sides. The formula for finding perimeter of a rectangle is P = 2l + 2w, where P = perimeter, l = the length of the rectangle, and w = the width of the rectangle.

Practice Exercise

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Problem Exercises

1.		Find the perimeter of a plywood sheet whose length is 4' and whose width is 8'.
			A)	12'
			B)	24'
			C)	32'
			D)	64'
2.		Find the perimeter of a sill plate that must rest on a rectangular foundation that is 40' long and 24' wide.
			A)	128'
			B)	64'
			C)	32'
			D)	16'
3.		The opening for a window is 48'' long and 32'' wide, so the perimeter of the opening is
			A)	16''.
			B)	80''.
			C)	160''.
			D)	320''.
4.		A remodeler estimated the crown molding needed for a 12' 6'' × 14' room using the perimeter of
			A)	26' 6''.
			B)	53'.
			C)	79' 6''.
			D)	106'.
5.		A job requires building a 10' × 13' deck, whose perimeter is
			A)	130'.
			B)	92'.
			C)	46'.
			D)	23'.