Question

find the reference angle of the given angle: 150 degrees(more info in comments)

Answer 1

here's the example from my textbook it said \[A=1/2ab \sin \theta\] =1/2(10)(3)sin 120
= 15 sin 60
15\[\sqrt{3}/2\] (they multiplied)
= about 13cm^2
but then i don't understand when the first problem says find the reference angle for the given angle