document.write( "Question 1185345: Find the area of a quadrilateral having the points (-3, 4), (-2, -1), (4, 4) and (0, 5)
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Algebra.Com's Answer #816162 by ikleyn(52797) $\"\"$ $\"About$

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\n" ); document.write( "Find the area of a quadrilateral having the points A(-3, 4), B(-2, -1), C(4, 4) and D(0, 5).
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document.write( "I will assume that the vertices of the quadrilateral go in that order as the points are listed.\r\n" );
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document.write( "Then I see that the diagonal AC of the quadrilateral is horizontal y=4 and divides the quadrilateral in two triangles.\r\n" );
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document.write( "Triangle ABC has the vertex  B  BELOW  the diagonal line y= 4. \r\n" );
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document.write( "It has the base AC of the length 4 - (-3) = 7 units and the altitude drawn to AC of the length 4 - (-1) = 5 units.\r\n" );
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document.write( "Hence, the area of the triangle ABC is   = 17.5 square units.\r\n" );
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document.write( "Next, triangle ADC has the vertex  D  ABOVE  the diagonal line y= 4. \r\n" );
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document.write( "It has the base AC of the length 4 - (-3) = 7 units and the altitude drawn to AC of the length 5 - 4 = 1 units.\r\n" );
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document.write( "Hence, the area of the triangle ADC is   = 3.5 square units.\r\n" );
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document.write( "Finally, the area of the quadrilateral ABCD is the sum of the areas of the triangles ABC and ADC\r\n" );
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document.write( "     = 17.5 + 3.5 = 21 square units.    ANSWER\r\n" );
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\n" ); document.write( "\n" ); document.write( "How Alan solved the problem, it assumes that the reader knows EVERYTHING in Geometry, including Analytic Geometry.\r
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\n" ); document.write( "\n" ); document.write( "In my view, it is absolutely unrealistic hypothesis.\r
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\n" ); document.write( "\n" ); document.write( "Much more closer to reality is to assume that the reader knows NOTHING except the basic knowledge.\r
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\n" ); document.write( "\n" ); document.write( "So I adapted my solution correspondingly.\r
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