 There are six trigonometrical ratios. Three are fundamental and other three are their reciprocals.
 The six trigonometrical ratios are
 sine
 cos
 tan
 cosec (reciprocal of sin)
 sec (reciprocal of cos)
 cot (reciprocal of tan)
 sine: The ratio of perpendicular to hypotenuse is called sine of an angle.
sine α = perpendicular/hypotenuse
sine α = p/h
 cos: The ratio of base to hypotenuse is called cosine of an angle.
cos α = base/hypotenuse
cos α = b/h
 tan: The ratio of perpendicular to base is called tangent of an angle.
tan α = perpendicular/base
tan α = p/b
 cosecant: The ratio of hypotenuse to perpendicular is called cosecant of an angle.
cosec α = hypotenuse/perpendicular
cosec α = h/p
 secant: The ratio of hypotenuse to base is called secant of an angle.
sec α = hypotenuse/base
sec α = h/b
 cot: The ratio of base to perpendicular is called cotangent of an angle.
cot α = base/perpendicular
cot α = b/p
 Trigonometric Tables:
angle\ratio  sin  cos  tan  cot  sec  cosec 
0°  0  1  0/1  1/0  1  0/1 
30°  1/2  √3/2  1/√3  √3  2/√3  2 
45°  1/√2  1/√2  1  1  √2  √2 
60°  √3/2  1/2  √3  1/√3  2  2/√3 
90°  1  0  1/0  0/1  1/0  1 
