In figure, if p is a transversal to lines q and r, q || r and ∠ 1 and ∠ 2  are in the ratio 3 : 2, find all angles from 1 to 8.
                 

Adjacent angles 1 and 2 form a linear pair.
⇒ ∠ 1 + ∠ 2 = 180° (Linear Pair Axiom)
     ∠ 1 : ∠ 2 = 3 : 2
          .^.. ∠ 1  = 3/5   x  180°   
                    = 108°
∠ 2 = (2/5) x 180  = 72° ---------- (1)
Lines p and q intersect.
⇒  ∠ 2 = ∠ 4 (Vertically opposite angles)
  .^.. ∠ 4  = 72° (from 1)
Since ∠ 3 and  ∠ 4  form a linear pair.
.^.. ∠ 3 = 180° - 72^o = 108° (same as (2))
   ∠ 4 = ∠ 6 = 72°  (Alternate interior angles)
   ∠ 3 = ∠ 5 = 108° (Alternate interior angles)
Lines p and r intersect
∠ 5 = ∠ 7 = 108° (Vertically opposite angles)
∠ 6 = ∠ 8  = 72°  (Vertically opposite angles) 
.^.. ∠ 1 = 108°, ∠ 5 = 108°, ∠ 2 = 72°,  ∠ 6 = 72°, ∠ 3 = 108°, ∠ 7 = 108°, ∠ 4 = 72°  
and ∠ 8 = 72°