Q. A bedroom door has a perimeter of 28 feet and an area of 40 square feet. What are the dimensions of the door?___ feet by ___ feet
Perimeter Equation: Let's denote the length of the door as l and the width as w. The perimeter of a rectangle is given by the formula P=2l+2w. Since we know the perimeter is 28 feet, we can write the equation 2l+2w=28.
Simplify Perimeter Equation: To simplify the equation, we can divide both sides by 2, which gives us l+w=14.
Area Equation: The area of a rectangle is given by the formula A=lw. We know the area is 40 square feet, so we can write the equation lw=40.
Solve System of Equations: We now have a system of two equations with two variables:1. l+w=142. lw=40We can solve this system by expressing one variable in terms of the other using the first equation. Let's solve for w: w=14−l.
Substitute Width: Substitute w from the previous step into the area equation: l(14−l)=40.
Expand Equation: Expand the equation: 14l−l2=40.
Rearrange Equation: Rearrange the equation to form a quadratic equation: l2−14l+40=0.
Factor Quadratic Equation: Factor the quadratic equation: l - \(10)(l - 4) = 0\
Solve for Length: Set each factor equal to zero and solve for l: l−10=0 or l−4=0, which gives us l=10 or l=4.
Possible Dimensions: Since l and w are interchangeable in a rectangle (one can be the length and the other the width), we have two possible dimensions for the door: 10 feet by 4 feet or 4 feet by 10 feet.
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