I'm a bit confused with this one. Cutting a Wire. A length of wire 16 inches is to be cut into two pieces, and then each piece will be bent to form a square. Find the length of the two pieces if the sum of the areas of the two squares is 10 square inches. Thank you!.
John F.2009-01-26T20:05:35Z
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First, make the first length of wire x and the second one 16 - x. Now convert the words to mathematical expressions. Since the two lengths of wire are bent to make squares, that must mean that they are bent into 4 equal portions. The portion of the first length is x/4 and the portion for the second length is (16 - x)/4).
When the length of one of these portions is squared, that gives you the area of a square. The sum of the areas of the two squares is 10. Set it up like this:
(x/4)^2 + ((16 - x)/4)^2 = 10
Now try to solve for x. First square the things inside the parenthesis,
(x^2/16) + ((256 - 32x + x^2)/16) = 10
You can combine the expressions because they have a common denominator of 16.
(2x^2 - 32x + 256)/16 = 10
Multiply both sides by 16 to cancel it out.
2x^2 - 32x + 256 = 160
Subtract 160 from both sides to get a quadratic equation.
2x^2 - 32x + 96 = 0
Factor out a 2 to make factoring the quadratic easier.
2(x^2 - 16x + 48) = 0
Now factor the quadratic and cancel out the 2 by dividing it.
(x - 12)(x - 4) = 0
x = 12, x = 4
The lengths of the two wires are 12 inches and 4 inches.