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The triangle with vertices at (1,0), (0,1), and (k,k) has area 1/2. Find k.     

 

A triangle with vertices (1,0), (0,1), and (0,0) has area 1/2.     

So does a triangle with vertices (1,0), (0,1), and (1,1)     

That would make k equal either 0 or 1.     

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