Begin by drawing a free body diagram of particle A, then apply the equations of equilibrium.
\begin{align}\\ \Sigma F_x = 0 \\-{T_B}_x + {T_C}_x = 0 \end{align} \\ T_B \cos(\var{a1}°) = T_C \sin(\var{90-a2}°) \qquad(1)
\begin{align}\\ \Sigma F_y = 0 \\{T_B}_y + {T_C}_y - W_1 = 0 \end{align} \\ T_B \sin(\var{a1}°) + T_C \cos(\var{90-a2})° = W_1 \qquad(2)
Solve (1) and (2) simultaneously for T_B and T_C.
T_B = \var{siground(TB,4)}, \quad T_C = \var{siground(TC,4)}
With T_C known, use a similar approach on particle C to find T_D and T_E.
Since cable CD is horizontal T_D has no y-component, so the \Sigma F_y = 0 equation only has one unknown and simultaneous equations are unnecessary in this case.
T_D = \var{siground(TD,4)}, \quad T_E = \var{siground(TE,4)}