In a right triangle, the "Sin" of an angle is the ratio of (the leg opposite the angle) to (the hypotenuse of the triangle).
If (sin of the angle) is 5/6, then the angle is in a right triangle where the leg opposite the angle is 5 and the hypotenuse is 6.
The other leg ... the one adjacent to that angle ... is √(6² - 5²).
That's √11 .
-- The (cosine of the angle) is
(leg adjacent to the angle) divided by (hypotenuse of the triangle).
That's √11/6 .
-- The (tangent of the angle) is
(leg opposite the angle) divided by (leg adjacent to the angle) .
That's 5/√11 .