document.write( "Question 965752: Please help me solve this question:A cone with the sector angle of 45 degree is cut out of a circle of radius rcm.Find the base radius of the cone. \n" ); document.write( "
Algebra.Com's Answer #590272 by Theo(13342)![]() ![]() You can put this solution on YOUR website! you cut out a sector of 45 degrees from the larger circle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the length of the arc of that sector is equal to 1/8 times the circumference of the larger circle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this is because arc length = 45/360 * 2*pi*r which makes arc length equal to 1/8 * 2*pi*r.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the arc length of the sector that you just cut out is the circumference of the base circle of the cone.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since the circumference of the base circle of the cone is 1/8 times the circumference of the larger circle, then it stands to reason that the radius of the base circle of the cone should be equal to 1/8 times the radius of the larger circle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "let r1 = the radius of the base circle of the cone. \n" ); document.write( "let r2 = the radius of the larger circle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c1 = circumference of the base circle of the cone. \n" ); document.write( "c2 = circumference of the larger circle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c1 = 2*pi*r1 \n" ); document.write( "c2 = 2*pi*r2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since c2 is equal to 8 times c1, we get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c1/c2 = 1/8 = (2*pi*r1) / (2*pi*r2)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since 2*pi in the numerator and denominator are the same, then cancel out, andyou are left with:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c1/c2 = 1/8 = r1/r2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the ratio of the circumference of the base circle to the larger circle is equla to 1/8 and the ratio of the radius of the base circle to the radius of the larger circle is also 1/8.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i believe that's what you're asking.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if it's any different, let me know.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |