What is the value of cos 45

EinsteinJr

Draw up any right angled isosceles triangle and you can get the exact value of any trig ratio for 45 degrees easily.   

It is usual and easiest if you make he legs 1 unit each but you don't have to :))

Thanks DarkBlaze, you have been giving a lot of good answers lately :)

cos(45)≈0.707106781187 (can't tell you what the exact value is becaus it's an irrational number, which has infinitely many numbers in its decimal part, and which isn't a real ratio of two integers)

cos 45 is part of the "special trigonometric functions".

In exact form, it is (sqrt 2)/2.

EinsteinJr gives a decimal approximation.