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Find the angle between the altitude $v_c$ and side $b$ in the triangle $ABC$ for $A=[1;2]$, $B=[7;-2]$ and $C=[6;1]$. Round to the nearest degree. Hint: In geometry, the altitude $v_c$ of the triangle $ABC$ is the line segment through the vertex $C$ and perpendicular to the line containing the opposite side of the triangle.