(a) Sine rule in the upper triangle: \(\sin x/41.3=\sin102^\circ/64.5\), giving \(\boxed{x=38.8^\circ}\). The other inverse-sine angle is impossible with the 102° angle.

(b) Cosine rule in the lower triangle: \(\cos y=(64.5^2+52.1^2-70.2^2)/(2(64.5)(52.1))\), giving \(\boxed{y=73.2^\circ}\).