document.write( "Question 1200226: Benjamin is drawing a triangle
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\n" ); document.write( "4 cm
\n" ); document.write( "10 cm
\n" ); document.write( "18 cm
\n" ); document.write( "21 cm
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Algebra.Com's Answer #834292 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "10 cm
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\n" ); document.write( "\n" ); document.write( "Explanation:\r
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\n" ); document.write( "\n" ); document.write( "We have a triangle with sides a,b, and c.\r
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\n" ); document.write( "\n" ); document.write( "a = 9 and b = 12 are the two known sides.
\n" ); document.write( "c is the unknown side.\r
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\n" ); document.write( "\n" ); document.write( "Due to the triangle inequality theorem, we have these three conditions that must all be true if we want a triangle to be possible
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\n" ); document.write( "Rephrased verbally: \"The sum of any two sides must exceed the third side\".\r
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\n" ); document.write( "\n" ); document.write( "Let's isolate c in the 1st two inequalities
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\n" ); document.write( "\n" ); document.write( "If b ≥ a, then we'll focus on b-a < c so that the left hand side is nonnegative.\r
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\n" ); document.write( "\n" ); document.write( "At the same time, the third inequality condition of the triangle inequality theorem states that c < a+b or c < b+a\r
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\n" ); document.write( "\n" ); document.write( "We have these inequalities
\n" ); document.write( "b-a < c and c < b+a
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\n" ); document.write( "b-a < c < b+a
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\n" ); document.write( "\n" ); document.write( "Summary of the previous section:\r
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\n" ); document.write( "\n" ); document.write( "Given a triangle with sides {a,b,c} where a & b are known lengths, and b ≥ a, the third side c has the restrictions of: b-a < c < b+a\r
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\n" ); document.write( "\n" ); document.write( "From here we plug in a = 9 and b = 12
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\n" ); document.write( "12-9 < c < 12+9
\n" ); document.write( "3 < c < 21\r
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\n" ); document.write( "\n" ); document.write( "The third side is between 3 cm and 21 cm, excluding each endpoint.
\n" ); document.write( "We cannot have c = 3. We also cannot have c = 21.
\n" ); document.write( "These endpoints will cause a straight line to form rather than a triangle.\r
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\n" ); document.write( "\n" ); document.write( "The following answer choices are in the interval mentioned:
\n" ); document.write( "4 cm
\n" ); document.write( "10 cm
\n" ); document.write( "18 cm

\n" ); document.write( "which are the final answers.
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