document.write( "Question 754364: AB is a chord of a circle centre O. The radius of the circle is 50 cm long and the length of AB is 60 cm. What is the distance of AB from O? \n" ); document.write( "
Algebra.Com's Answer #459010 by Cromlix(4381)\"\" \"About 
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A Pythagorean question.
\n" ); document.write( "Consider a line coming from centre O
\n" ); document.write( "and meeting the chord AB at its centre.
\n" ); document.write( "The chord would be divided into two pieces
\n" ); document.write( "each measuring 30cm.
\n" ); document.write( "Now if we swing a radius round to extend
\n" ); document.write( "from centre O to where AB touches the circumference
\n" ); document.write( "of the circle.
\n" ); document.write( "We now have a right angled triangle.
\n" ); document.write( "The radius is the hypotenuse, half of AB is the
\n" ); document.write( "base and the line from the centre to the chord
\n" ); document.write( "is the height.
\n" ); document.write( "By applying Pytagoras: the sum of the two sides
\n" ); document.write( "squared = the hypotenuse squared.
\n" ); document.write( "By adjusting the formula we find that if we take
\n" ); document.write( "the hypotenuse squared and take away from it,
\n" ); document.write( "the base squared, the answer when it is square
\n" ); document.write( "rooted = the distance from the centre O to the chord AB.
\n" ); document.write( " 50^2 - 30^2 = the height^2
\n" ); document.write( " height^2 = 1600
\n" ); document.write( " height = 40 cm.
\n" ); document.write( "This is the distance from the centre O to the chord AB.
\n" ); document.write( "Hope this helps
\n" ); document.write( ":-)
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