Question

Trig question...

Answer 1

here's the question

Answer 2

Hmmm :\

Answer 3

hint:
if we apply the formula for area of a triangle, then we can write this:
\[\Large area = \frac{1}{2}XY \times YZ \times \sin \left( {\angle XYZ} \right)\]

Answer 4

they are talking about the ambiguous angles in sin case. Your triangle should look like this :


you need to use the formula for the triangle, so since the formula is:
\[Area= \frac{ 1 }{ 2 }ab*sinx\]
\[31 = \frac{ 1 }{ 2 } *13*9 *\sin x\]
\[sinx = \frac{ 31 }{ \frac{ 1 }{ 2 }*9*13 } = 0.5299\]
\[x=\sin ^{-1}(0.5299) = 31.99°\]

so since this a ambiguous case the other angle will be
180 - 31.99 = 148°