document.write( "Question 1200226: Benjamin is drawing a triangle
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document.write( "and knows that two sides are
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document.write( "9 centimeters and 12 centimeters.
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document.write( "What could the third side length be?
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document.write( "Select all that apply
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document.write( "2 cm
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document.write( "4 cm
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document.write( "10 cm
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document.write( "18 cm
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document.write( "21 cm \n" );
document.write( "
Algebra.Com's Answer #834292 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Answers: \n" ); document.write( "4 cm \n" ); document.write( "10 cm \n" ); document.write( "18 cm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "=============================================================================\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Explanation:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have a triangle with sides a,b, and c.\r \n" ); document.write( " \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 \n" ); document.write( " \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 \n" ); document.write( "a < b+c \n" ); document.write( "b < a+c \n" ); document.write( "c < a+b \n" ); document.write( "Rephrased verbally: \"The sum of any two sides must exceed the third side\".\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's isolate c in the 1st two inequalities \n" ); document.write( "a < b+c becomes a-b < c \n" ); document.write( "b < a+c becomes b-a < c\r \n" ); document.write( " \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 \n" ); document.write( " \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have these inequalities \n" ); document.write( "b-a < c and c < b+a \n" ); document.write( "they can be conveniently glued together to get \n" ); document.write( "b-a < c < b+a \n" ); document.write( "This gives a range of possible c values where b ≥ a.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "---------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Summary of the previous section:\r \n" ); document.write( " \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 \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "From here we plug in a = 9 and b = 12 \n" ); document.write( "b-a < c < b+a \n" ); document.write( "12-9 < c < 12+9 \n" ); document.write( "3 < c < 21\r \n" ); document.write( " \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 \n" ); document.write( " \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. \n" ); document.write( " \n" ); document.write( " |