document.write( "Question 879405: A chord of a circle is 18cm long and subtends an angle of 100 degree at the center. find the radius of the circle. \n" ); document.write( "

Algebra.Com's Answer #530798 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "The given chord is in red.  The radius in r.  We want to find r. \r\n" );
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document.write( "Draw a perpendicular line from the center to the red chord, which\r\n" );
document.write( "divides the 18cm chord into two 9cm line segments, and divides\r\n" );
document.write( "the 100° angle into two 50° angles:\r\n" );
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document.write( "Looking only at the upper right triangle:\r\n" );
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document.write( "9cm is the side opposite the 50° angle\r\n" );
document.write( "and r is the hypotenuse:\r\n" );
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document.write( "The trig ratio that involves the opposite and the hypotenuse is the\r\n" );
document.write( "sine.\r\n" );
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document.write( "Multiply both sides by r:\r\n" );
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document.write( "Divide both sides by sin(50°)\r\n" );
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document.write( "cm. \r\n" );
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document.write( "Edwin

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