Question

given cos sigma = -12/13, sigma in quadrant III, how would you go about to find the remaining trig functions of sigma?

Answer 1

the right angled triangle with two sides of 12 and 13 is special its one which has 3 sides of lengths which are whiole numbers
hypotenuse = 13 and two legs are 5 and 12

Answer 2

adj side= 12
hypt = 13
so oposite side = 5

this is the triangle formed by your angle

Answer 3

ok and would the sigma be the 90 degree angle then?

Answer 4

sine sigma = -5/13
tan sigma = -5 / -12 = 5/12