Question 978118
The reference angle is the angle {{{A}}} in the first quadrant,
{{{0^o<=A<=90^o}}} , whose trigonometric functions are the same,
except for (maybe) a minus sign.
To find it, you just find the reflection of your angle that will fall into the first quadrant.
{{{3(90^o)=370^o<307^o,360^o=4(90^o)}}} so {{{theta=307^o}}} is in the fourth quadrant.
{{{drawing(400,400,-0.98,0.98,-0.98,0.98,grid(0),
arrow(0,0,0.722,-0.958),arc(0,0,0.82,0.82,53,360),
locate(-0.3,-0.15,307^o),
blue(arc(0,0,1.8,1.8,0,53)),locate(0.32,-0.15,blue(360^o-307^o=53^o)),
green(arrow(0,0,0.72,0.958)),
green(arc(0,0,1.7,1.7,-53,0)),locate(0.75,0.5,A=highlight(green(53^o)))
)}}}