There is no figure, so I asume the angle of the rope is measured with respect to the horizontal direction.
If this is the case, then the magnitude of the tension is the hypothenuse of a right triangle, of which

and

(horizontal and vertical component of the tension) are the other sides, and

is the angle between T and

.
Therefore,

(the side of the triangle opposite to

) is given by the magnitude of the tension multiplied by the sine of the angle:
