# A very long name

Geometry Level 3

\begin{aligned} a+b+c-d &=& 16 \\ a+b-c+d &=& 30 \\ a-b+c+d &=& 35 \\-a+b+c+d &=& 42 \end{aligned}

If constants $a,b,c,d$ satisfy the system of equations above, find the area of a cyclic quadrilateral with sides $a,b,c,d$.

Inspiration

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