document.write( "Question 576246: What is the area of an equilateral triangle that has an altitude of 9? \n" ); document.write( "
Algebra.Com's Answer #369765 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
What is the area of an equilateral triangle that has an altitude of 9?
\n" ); document.write( "An equilateral triangle tells us that all three sides are equal.
\n" ); document.write( "Area = (1/2)bh
\n" ); document.write( "first, we need to find the length of the base
\n" ); document.write( "Let b = length of base
\n" ); document.write( "then from Pythagorean theorem we have
\n" ); document.write( "(b/2)^2 + 9^2 = b^2
\n" ); document.write( "b^2/4 + 81 = b^2
\n" ); document.write( "81 = b^2 - b^2/4
\n" ); document.write( "81 = b^2(1 - 1/4)
\n" ); document.write( "81 = b^2(3/4)
\n" ); document.write( "81(4/3) = b^2
\n" ); document.write( "81(4/3) = b^2
\n" ); document.write( "108 = b^2
\n" ); document.write( "10.39 = b
\n" ); document.write( ".
\n" ); document.write( "Area = (1/2)bh
\n" ); document.write( "Area = (1/2)(10.39)(9)
\n" ); document.write( "Area = 46.77 \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );