Answer:
√3/2 or 0.866
Step-by-step explanation:
Use special triangles. (See attachment)
The cosine ratio is adjacent ÷ hypotenuse.
cos30° = √3 ÷ 2 = √3/2
As a decimal, cos30° ≈ 0.866
Remember all the primary trig ratios with the acronym SohCahToa.
"o" = opposite
"a" = adjacent
"h" = hypotenuse
S, C and T are sin, cos, tan
