C2 2017 2 Edexcel

A diagram helps:

Using the sine rule:

\dfrac {\sin 50} {13} = \dfrac {\sin x} {16}

Then:

\displaystyle \sin x = \frac {16} {13} \sin 50

So either:

\displaystyle x = \arcsin \left(\frac {16} {13} \sin 50\right) = 70.53\ldots = 70.5 \text { (1dp)}

or:

\displaystyle x = 180 - \arcsin \left(\frac {16} {13} \sin 50\right) = 109.47\ldots = 109.5 \text { (1dp)}

1 Like

:+1: :+1: :+1: :+1: :+1: