Question

It is planned to build a bridge AB across the river.

Calculate the length of the bridge if the base BC

= 165 m, ß = 108 °, y = 20 °

Answer 1

To calculate the length of the bridge we use sine rule

$\frac{c}{sineC}=\frac{a}{sineA}$

Therefore,

$\frac{c}{sine20°}=\frac{165°}{sine52°}$

Cross multiply to get the unknown value

$c=\frac{165sine20°}{sine52°}$

$c=152.68m$

Therefore, the length of the bridge will be

$152.68m$