Given the shown triangle
Using cosine laws
[tex]c^2=a^2+b^2-2abcos(C)[/tex][tex]c^=\sqrt{a^2+b^2-2abcos(C)}[/tex]
where
b=
[tex]b=\frac{21sin(81)}{sin(9)}[/tex][tex]b=132.59[/tex]
then
[tex]c=\sqrt{a^2+b^2-2abcos(C)}[/tex][tex]c=\sqrt{21^2+132.59^2-2(21)(132.59)cos(90)}[/tex][tex]c=134.24[/tex]
WS= 134.24
