2010014610
Level:
B
Given points \(A = [4;-1]\),
\(B = [2,-3]\) and
\(C = [5,5]\), find the angle
\(\beta \) (the interior angle
at the vertex \(B\))
in the triangle \(ABC\).
\(24^{\circ }27'\)
\(144^{\circ }46'\)
\(155^{\circ }33'\)
\(11^{\circ }05'\)