document.write( "Question 1203040: Please help me with this
\n" ); document.write( "The sides of a triangle have lengths 11, 15, and k where k is an integer. For how many values of k, is
\n" ); document.write( "the triangle obtuse?
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Algebra.Com's Answer #838283 by greenestamps(13203)\"\" \"About 
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\n" ); document.write( "In a right triangle with the standard notation with c being the length of the longest side (hypotenuse), the relationship \"c%5E2=a%5E2%2Bb%5E2\" holds.

\n" ); document.write( "For a triangle to be obtuse, again using c to denote the length of the longest side, the relationship \"c%5E2%3Ea%5E2%2Bb%5E2\" must hold.

\n" ); document.write( "In this problem, there are two cases to consider -- the longest side can be either k or 15.

\n" ); document.write( "(1) k is the longest side

\n" ); document.write( "The triangle inequality tells us that k<11+15=26.

\n" ); document.write( "For the triangle to be obtuse, we need to have

\n" ); document.write( "\"k%5E2%3E11%5E2%2B15%5E2\"
\n" ); document.write( "\"k%5E2%3E346\"
\n" ); document.write( "\"k%3E18.6\" approximately

\n" ); document.write( "The integers greater than 18.6 and less than 26 are 19 through 25 inclusive -- that's 7 possible integer values for k.

\n" ); document.write( "(2) 15 is the longest side

\n" ); document.write( "Now the triangle inequality tells us k>15-11=4.

\n" ); document.write( "For the triangle to be obtuse, we need to have

\n" ); document.write( "\"15%5E2%3Ek%5E2%2B11%5E2\"
\n" ); document.write( "\"225-121%3Ek%5E2\"
\n" ); document.write( "\"k%5E2%3C104\"
\n" ); document.write( "\"k%3C10.2\" approximately

\n" ); document.write( "The integers greater than 4 and less than 10.2 are 5 through 10 inclusive -- that's 6 possible integer values for k.

\n" ); document.write( "ANSWER: 7+6 = 13

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