uitwerking 1

$ \eqalign{ & AS = x\,\,en\,\,CS = h \cr & SB = 120 - x \cr & \tan (60^\circ ) = \frac{h} {x} \Rightarrow h = x \cdot \tan (60^\circ ) \cr & \tan (40^\circ ) = \frac{h} {{120 - x}} \Rightarrow h = \left( {120 - x} \right) \cdot \tan (40^\circ ) \cr & x \cdot \tan (60^\circ ) = \left( {120 - x} \right) \cdot \tan (40^\circ ) \cr & x \cdot \tan (60^\circ ) = 120 \cdot \tan (40^\circ ) - x \cdot \tan (40^\circ ) \cr & x \cdot \tan (60^\circ ) + x \cdot \tan (40^\circ ) = 120 \cdot \tan (40^\circ ) \cr & x \cdot \left( {\tan (60^\circ ) + \tan (40^\circ )} \right) = 120 \cdot \tan (40^\circ ) \cr & x = \frac{{120 \cdot \tan (40^\circ )}} {{\tan (60^\circ ) + \tan (40^\circ )}} \approx {\text{39}}{\text{,2}} \cr & h = {\text{39}}{\text{,2}} \cdot \tan (60^\circ ) \approx 67,8 \cr} $