document.write( "Question 1108272: The perimeter of a right triangle is 144 cm. The base is 12 cm. less than the adjacent. Find the area. \n" ); document.write( "
Algebra.Com's Answer #723296 by KMST(5328)\"\" \"About 
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The easiest way to calculate the area of a right triangle is
\n" ); document.write( "\"area=%281%2F2%29%2Aleg%5B1%5D%2Aleg%5B2%5D\" ,
\n" ); document.write( "because the legs are perpendicular to each other,
\n" ); document.write( "so one leg can be considered the base, and the other is the height.
\n" ); document.write( "The difficult part is calculating the length of those legs.
\n" ); document.write( "The sides of the triangle measure
\n" ); document.write( "\"leg%5B1%5D=36cm\" , \"leg%5B2%5D=48cm\" and \"hypotenuse=60cm\" .
\n" ); document.write( "In this case,
\n" ); document.write( "\"area=%281%2F2%29%2A%2836cm%29%2A%2848cm%29=highlight%28864cm%5E2%29\"
\n" ); document.write( "How did I know the leg length?
\n" ); document.write( "
\n" ); document.write( "THE GET RESULTS WITHOUT MUCH WORK WAY:
\n" ); document.write( "Looking at a list of Pythagorean triples,
\n" ); document.write( "or looking at multiples of the popular 3-4-5 triple,
\n" ); document.write( "we figure that 36-48-60 (the 3-4-5 triple times 12)
\n" ); document.write( "add up to 144, and there are differences of 12 between the numbers.
\n" ); document.write( "The sum of the numbers, and differences between numbers in 3-4-5
\n" ); document.write( "are 12 and 1 respectively, so after multiplying everything times 12,
\n" ); document.write( "the sum and differences are
\n" ); document.write( "\"23%2A12=144\" and \"1%2A12=12\"
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\n" ); document.write( "THE EXPECTED WAY:
\n" ); document.write( "If there is a figure, it may suggest that
\n" ); document.write( "the \"base\" is one leg of the right triangle.
\n" ); document.write( "If we think the base is the shorter leg,
\n" ); document.write( "\"the adjacent\" can be taken to mean the other leg or the hypotenuse.
\n" ); document.write( "If we think the base is the longer leg, then \"the adjacent\" must be the hypotenuse.
\n" ); document.write( "Either way, what follows is not fun.
\n" ); document.write( "If we think \"the adjacent\" is the hypotenuse,
\n" ); document.write( "the lengths of the sides of the triangle, in cm, are:
\n" ); document.write( "\"x\"= hypotenuse,
\n" ); document.write( "\"x-12\"= the \"base\" leg,
\n" ); document.write( "\"sqrt%28x%5E2-%28x-2%29%5E2%29\"=the other leg, and
\n" ); document.write( "the perimeter (in cm) is
\n" ); document.write( "\"x%2Bx-12%2Bsqrt%28x%5E2-%28x-12%29%5E2%29=144\"
\n" ); document.write( "\"2x-12%2Bsqrt%28x%5E2-%28x%5E2-24x%2B144%29%29=144\"
\n" ); document.write( "\"2x-12%2Bsqrt%28x%5E2-x%5E2%2B24x-144%29=144\"
\n" ); document.write( "\"2x-12%2Bsqrt%2824x-144%29=144\"
\n" ); document.write( "\"sqrt%2824x-144%29=144%2B12-2x\"
\n" ); document.write( "\"sqrt%2824x-144%29=156-2x\"
\n" ); document.write( "If we get smart, our next step is
\n" ); document.write( "\"2sqrt%286x-36%29=156-2x\" ,
\n" ); document.write( "an then we simplify, dividing both sides by 2,to get
\n" ); document.write( "\"sqrt%286x-36%29=78-x\" .
\n" ); document.write( "Squaring both sides of the equal sign, we get
\n" ); document.write( "\"6x-36=6084-156%2Bx%5E2\"
\n" ); document.write( "\"x%5E2-156x-6x%2B6084%2B36=0\"
\n" ); document.write( "\"x%5E2-162x%2B6120=0\"
\n" ); document.write( "AT that point, we may be able to factor it as
\n" ); document.write( "\"%28x-60%29%28x-102%29=0\" .
\n" ); document.write( "The solutions to that equation are \"x=60\" and \"x=102\" .
\n" ); document.write( "We discard \"x=102\" ,
\n" ); document.write( "because it is not a solution of \"sqrt%286x-36%29=78-x\" .
\n" ); document.write( "It is just an extraneous solution we introduced when we squared both sides.
\n" ); document.write( "The conclusion is that the hypotenuse measures \"60cm\" ,
\n" ); document.write( "the base measures \"60cm-12cm=48cm\" ,
\n" ); document.write( "and the length of the other leg, in cm, is
\n" ); document.write( "
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\n" ); document.write( "If there is another way that is simple, let me know.
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