document.write( "Question 1111119: ABCD is a square with side length x cm. M and N are the midpoints of AD and CD respectively. The midpoints and point B make a triangle which is the shaded area. Find the ratio of the shaded to unshaded area. \n" ); document.write( "
Algebra.Com's Answer #726202 by KMST(5328)![]() ![]() You can put this solution on YOUR website! THE PICTURE: \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "THE FIFTH_GRADER'S SOLUTION: \n" ); document.write( "If we connect M to the midpoint of BC, \n" ); document.write( "and N to the midpoint of AB, we split the square into 4 smaller squares, each one being \n" ); document.write( "Joining 2 of those small squares we would get a rectangle \n" ); document.write( "that is \n" ); document.write( "One of those 4 smaller squares \n" ); document.write( "is divided into two equal triangular parts by diagonal MN, \n" ); document.write( "so each of those two triangles is \n" ); document.write( "Triangle MND is \n" ); document.write( " \n" ); document.write( "The diagonal of a rectangle that is \n" ); document.write( "(such as diagonal MB), \n" ); document.write( "divides the rectangle into two equal triangles. \n" ); document.write( "Each of those triangles is \n" ); document.write( "Triangle ABM is \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "The unshaded area is triangles ABM + NCB + MND, and amounts to \n" ); document.write( " \n" ); document.write( "So, the shaded area is \n" ); document.write( " \n" ); document.write( "Obviously the ratio of shaded area to unshaded area is \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "THE EXPECTED SOLUTION is probably as follows \n" ); document.write( "As ABCD is a square with side length \n" ); document.write( " \n" ); document.write( "As \"M and N are the midpoints of AD and CD respectively\", \n" ); document.write( " \n" ); document.write( "The unshaded area is made up of triangles \n" ); document.write( "so its total area is easy to calculate. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Calculating the shaded area as the area of triangle MNB may seem difficult, \n" ); document.write( "However, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "So, \n" ); document.write( "The ratio of those two area values, both in \n" ); document.write( " |