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* B - O = S1 + S2 = (40, 0) + (20*cos(- 150°), 20*sin(- 150°)) =
= (40, 0) + (20*(- √3/2), 20*(- 1/2)) =
= (40 - 10*√3, - 10)
* |B - O| = √((40 - 10*√3)^2 + (- 10)^2) = 20*√(5 - 2*√3) ~= 24.786 km