Tuesday, August 31, 2010

#6 Math error discussion (Coordinate Geometry)

A question was asked in the pre board examination from the chapter Coordinate Geometry which was the application of distance formula.


Show that the points A(1,7) , B(4,2), C(-1,-1) and D(-4,4) are the vertices of a square.


Most of the students did the following...
There are two types of errors in this solution.
First one is a calculation error, 25+9 is not 36.
The second one is a conceptual error. It is important to note that when you are asked to prove that given 4 points are vertices of a square then you need to show that AB=BC=CD=DA and lengths of both the diagonals are equal i.e. AC = BD.

Remember this!!

geometry distance formula

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