What could be the possible answer?

Opposite of theta is 8, adjacent is 3

hypotenuse is √(8²+3²) = √73

cos theta = adj/hyp = 3/√73

tan theta = opp/adj = 8/3

csc theta = 1/sin theta = hyp/opp =  √73/8

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: