document.write( "Question 468811: the side of a triangle are 70 cm, 80cm and 90cm. compute the lenght of the altitude to the 80 cm side. \n" ); document.write( "
Algebra.Com's Answer #321645 by lwsshak3(11628)\"\" \"About 
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the side of a triangle are 70 cm, 80cm and 90cm. compute the length of the altitude to the 80 cm side
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\n" ); document.write( "Draw a triangle with sides 70 cm, 80 cm and 90 cm. From the apex opposite the 80 cm side drop a perpendicular to the 80 cm side which divides the side into two parts. Let x=one of the parts and (80-x) the other part. We now have two right triangles to work with. One right triangle has legs of x and the altitude(h) and hypotenuse of 90. The other right triangle has legs of (80-x) and the same altitude(h) and a hypotenuse of 70.
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\n" ); document.write( "calculations:
\n" ); document.write( "h^2=70^2-(80-x)^2
\n" ); document.write( "h^2=90^2-x^2
\n" ); document.write( "..
\n" ); document.write( "70^2-(80-x)^2=90^2-x^2
\n" ); document.write( "4900-6400+160x-x^2=8100-x^2
\n" ); document.write( "160x=9600
\n" ); document.write( "x=60
\n" ); document.write( "h^2=90^2-x^2=8100-3600=4500
\n" ); document.write( "h=√4500=67.1 cm
\n" ); document.write( "ans:
\n" ); document.write( "Length of altitude to the 80 cm side=67.1 cm \n" ); document.write( "
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