document.write( "Question 964200: How to calculate the relative amounts of colour needed for a diamond shape?\r
\n" ); document.write( "\n" ); document.write( "As part of our assignment we have to create our own design for a quilt and I choose to do a diamond, but I need to calculate the amount of colour I would need but I do not know how to do it. \r
\n" ); document.write( "\n" ); document.write( "The functions that I have used to create the outer diamond are:
\n" ); document.write( "y=x+15 (-15< x <0)
\n" ); document.write( "y=-x-15 (-15< x <0)
\n" ); document.write( "y=x-15 (0< x <15)
\n" ); document.write( "y=-x+15 (0< x <15)\r
\n" ); document.write( "\n" ); document.write( "These functions are for the inner diamond:
\n" ); document.write( "y=x+10 (-10< x <0)
\n" ); document.write( "y=x-10 (0< x <10)
\n" ); document.write( "y=-5/5x+10 (0< x <10)
\n" ); document.write( "y=-5/5x-10 (-10< x <0)
\n" ); document.write( "

Algebra.Com's Answer #589340 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
I would think that by
\n" ); document.write( "y=-5/5x+10 you mean \"y=-%285%2F5%29x%2B10\" , or simply \"y=-x%2B10\" ,
\n" ); document.write( "and that by
\n" ); document.write( "y=-5/5x-10 you mean \"y=-%285%2F5%29x-10\" , or simply \"y=-x-10\" .
\n" ); document.write( "Those equations make a design like this:
\n" ); document.write( " showing nested diamonds (or really nested squares).
\n" ); document.write( "If calculating areas was necessary, we know that the area of a rhombus is half the product of the diagonal lengths.
\n" ); document.write( "So, the area of the large square is \"%281%2F2%29%2A30%2A30=450\" square units,
\n" ); document.write( "and the area of the smaller square is \"%281%2F2%29%2A20%2A20=200\" square units.
\n" ); document.write( "We could invoke a lot of higher math, but not even the calculation of areas above is necessary to find the ratio of the areas.
\n" ); document.write( "
\n" ); document.write( "I appreciate your effort at using math to describe the design.
\n" ); document.write( "without that (or a picture) I would have no idea of what your design was.
\n" ); document.write( "The description was complicated, but the calculation is very simple,
\n" ); document.write( "as in fifth grade math.
\n" ); document.write( "
\n" ); document.write( "The smaller, inside square's diagonals are \"2%2F3\" as long as
\n" ); document.write( "the larger, outside square's diagonals.
\n" ); document.write( "The inside square is a \"2%2F3\" scaled-down version of the outside one.
\n" ); document.write( "Its inside square's sides are \"2%2F3\" the length of the outside square's sides,
\n" ); document.write( "and as a consequence, the inside square's area is
\n" ); document.write( "\"%282%2F3%29%282%2F3%29=4%2F9\" the area of the outside square.
\n" ); document.write( "
\n" ); document.write( "If you are going to cut squares in two sizes and sew one on top of another,
\n" ); document.write( "for every 9 feet of material for the larger square you will need 4 feet of material for the smaller square.
\n" ); document.write( "
\n" ); document.write( "If, however, you are going to saw 4 trapezoids of the outside color,
\n" ); document.write( "forming a frame around the inside square,
\n" ); document.write( "that frame will be \"1-4%2F9=9%2F9-4%2F9=blue%285%2F9%29\" of the area of the large outside square,
\n" ); document.write( "and since the smaller inside square has \"green%284%2F9%29\" of the area of the large outside square,
\n" ); document.write( "so the ratio of visible material areas is \"blue%285%29%3Agreen%284%29\" in favor of the outside color.
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