document.write( "Question 746229: please help me solve this equation ; the circle is divided into 4 parts a,b,c,d where part a & c form a semicircle and part b&d form the other semicircle area of part a to area of part c is in the ratio 1: 3 the area of part b to the area of part d is in the ratio 1:2. the area of part c is bigger than part b by 20 SquareCentimeters find the area of the whole cirle \n" ); document.write( "
Algebra.Com's Answer #454196 by savvyhush23(50)\"\" \"About 
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please help me solve this equation ; the circle is divided into 4 parts a,b,c,d where part a & c form a semicircle and part b&d form the other semicircle area of part a to area of part c is in the ratio 1: 3 the area of part b to the area of part d is in the ratio 1:2. the area of part c is bigger than part b by 20 SquareCentimeters find the area of the whole cirle.
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\n" ); document.write( "Ok, let solve it one by one,
\n" ); document.write( "Let,
\n" ); document.write( "At = Total area of circle
\n" ); document.write( "Aa = Area of a
\n" ); document.write( "Ab = Area of b
\n" ); document.write( "Ac = Area of c
\n" ); document.write( "Ad = Area of d
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\n" ); document.write( "part a & c form a semicircle...part b&d form the other semicircle:
\n" ); document.write( "\"At%2F2+=+Aa+%2B+Ac\", and \"At%2F2+=+Ab+%2B+Ad\"
\n" ); document.write( "part a to area of part c is in the ratio 1:3...\"Aa%2FAc=1%2F3\", or \"Ac=3Aa\"
\n" ); document.write( "part b to the area of part d is in the ratio 1:2...\"Ab%2FAd=1%2F2\", or \"Ad=2Ab\"
\n" ); document.write( "the area of part c is bigger than part b by 20...\"Ac+=+Ab+%2B+20\"
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\n" ); document.write( "Ok, here is my favorite part:
\n" ); document.write( "We have 5 unknown (At, Aa, Ab, Ac, and Ad), so we have to form 5 equations to solve it. The 4 equations are ready above,
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\n" ); document.write( "since a & c and b & d are semi circle, \"At%2F2=At%2F2\", equation 5
\n" ); document.write( "we have the 2 equations for that above, substituting here, \"Aa+%2B+Ac+=+Ab+%2B+Ad\", or \"-Aa+%2B+Ab+-+Ac+%2B+Ad+=+0\", then add this to the other 3 remaining equation:
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\n" ); document.write( "but \"+Aa+=+Ac%2F3\" and \"Ab=Ac-20\", so, \"2%28Ac%2F3%29+%2B+2%28Ac-20%29-+Ac+-+20=0\",
\n" ); document.write( "So, \"Ac+=+36+cm%5E2\", \"Ab+=+16+cm%5E2\", \"Ad=32+cm%5E2\", and \"Aa=12+cm%5E2\"
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\n" ); document.write( "Therefore, \"At+=+Aa+%2B+Ab+%2B+Ac+%2B+Ad+=+96+cm%5E2\"\r
\n" ); document.write( "\n" ); document.write( "Check it, the value of individual area must satisfy the given ratio.
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