In the ABC triangle, the angle c is 90 cosA 1/5. Find sin B.

triangular ABC, ∡ с – straight line.
1) The ratio of the opposite leg to the hypotenuse is equal to the sine of the acute angle.
sin a = bc / ab;
sin b = ac / ab;
2) The ratio of the adjacent leg to the hypotenuse is equal to the cosine of the acute angle.
cos a = ac / ab;
cos b = bc / ab;
3) Find sin b if cos a = 1/5.
sin b = ac / ab and cos a = ac / ab;
sin b = cos a;
sin b = 1/5;
sin b = 0.2.