Chapter 2 - Force Vectors - Section 2.3 - Vector Addition of Forces - Problems - Page 32: 31

$\theta = 90°$ $F_{B} = 1KN$ $F_{R} = 1.73KN$

For $F_{B}$ to be minimum, it has to necessarily to be perpendicular to $F_{R}$; therefore: $\theta = 90°$ By applying trigonometry laws: $F_{R} =2 \times \sin(30°) = 1KN$ $F_{R} = 2\times \cos(30°) = 1.73KN$