Answer :

1. sin ∠YWX refers to the sin of the angle formed by the points YWX with X as the vertex

sin = opp/hyp

therefore sin ∠YWX = 40/41

2. cos ∠STR refers to the cosine of the angle formed by the points STR with T as the vertex

cos = adj/hyp

therefore cos ∠STR = 12/13

3. tan ∠YXZ refers to the tangent of the angle formed by the points YXZ with X as the vertex

tan = opp/adj

therefore tan ∠YXZ = d/c

4. tan ∠ZYX refers to the tangent of the angle formed by the points ZYX with Y as the vertex

tan = opp/adj

therefore tan ∠ZYX = c/d