Cosine is 0.5
at a 45 degree angle, or pi/4
cos(50) = 0.6428 (rounded)
Cos(65 deg) = 0.4226 approx.
As a decimal: 0.866 As a fraction: √(3)/2
Its supplementary angle is 121 degrees
An acute angle
Fora right angle triangle: cosine angle = adjacent/hypotenuse
Find the cosine of 38 degrees and then find its reciprocal.
The number 1.414... (square root of 2) is two times the cosine or sine of a 45 degree angle. The reason for this is that for a 45 degree angle, the two sides are cosine and sine, they are equal, and if you solve using the Pythagorean theorem with a hypotenuse of 1, the two sides are each (21/2)/2.