Answer:
D
Explanation:
the three main trig functions are
sin = opposite / hypotenuse
cos = adjacent / hypotenuse
tan = opposite / adjacent
( opposite = side opposite of angle , hypotenuse = longest side and adjacent = other side )
Sin(55) = a/c as side a is opposite of the angle and c is the hypotenuse so D might be the answer
cos(55) would be b/c as the adjacent of that angle is b and the hypotenuse is c. B and C show the wrong ratios so B and C can't be the answer
tan(55) would be a/b as side a is opposite of the angle and b is the adjacent, A says c/a which is wrong
so we can conclude the answer is D