Triginometry

You can find the area of any triangle using: area = 1/2bcsin A or area = 1/2acsin B or area = 1/2absin C

Radians, arcs, and sectors Arc length of sector = radius x central angle Area of sector = (central angle x radius squared) / 2 To convert degrees to radians, multiply by pi/180 To convert radians to degrees, multiply by 180/pi

Application of right-angled triangle trigonometry The angle of elevation is the angle 'up' from horizontal The angle of depression is the angle 'down' from horizontal The four cardinal compass points are north (N) south (S) east (E) west (W) Three-figure bearings give directions as clockwise from north