document.write( "Question 900733: The radius of the base of each of two right circular cones is 8 inches. The altitude of the first cone is 9 greater than that of the second cone and its slant height is 7 inches greater than that of the second. Find the altitude of the taller cone. \n" ); document.write( "
Algebra.Com's Answer #546554 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! The radius of the base of each of two right circular cones is 8 inches. \n" ); document.write( " The altitude of the first cone is 9 greater than that of the second cone \n" ); document.write( " and its slant height is 7 inches greater than that of the second. \n" ); document.write( " Find the altitude of the taller cone. \n" ); document.write( ": \n" ); document.write( "This can be done by considering two right triangles, using pythag formulas \n" ); document.write( "let x = the height of taller cone \n" ); document.write( "then \n" ); document.write( "(x-9) = the height of the smaller cone \n" ); document.write( "The slant dimensions are the hypotenuses \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "square both sides \n" ); document.write( " \n" ); document.write( "subtract x^2 from both sides \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "simplify, change the signs, divide by -2 \n" ); document.write( " \n" ); document.write( "square both sides \n" ); document.write( "49(x^2 + 64) = 81x^2 - 288x + 256 \n" ); document.write( "49x^2 + 3136 = 81x^2 - 288x + 256 \n" ); document.write( "combine like terms on the right \n" ); document.write( "0 = 81x^2 - 49x^2 - 288x + 256 - 3136 \n" ); document.write( "0 = 32x^2 - 288x - 2880 \n" ); document.write( "simplify divide by 32 \n" ); document.write( "x^2 - 9x - 90 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(x-15)(x+6) = \n" ); document.write( "the positive solution here \n" ); document.write( "x = 15 in is the altitude of the taller cone \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "See if that checks out the height of the smaller will be 6 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "---------------------- \n" ); document.write( "slant differences 7 in \n" ); document.write( " |