
DOB is a straight line.
∴ \(\angle\)DOC + \(\angle\)COB = 180°
⇒ \(\angle\)DOC = 180° − 125° = 55°
In ∆DOC,
\(\angle\)DCO + \(\angle\)CDO + \(\angle\)DOC = 180° (The sum of the measures of the angles of a triangle is 180°)
⇒ \(\angle\)DCO + 70º + 55º = 180°
⇒ \(\angle\)DCO = 55°
It is given that ∆ODC ∼ ∆OBA.
∴ \(\angle\)OAB = \(\angle\)OCD [Corresponding angles are equal in similar triangles]
⇒ \(\angle\)OAB = 55°

In the adjoining figure, \( AP = 1 \, \text{cm}, \ BP = 2 \, \text{cm}, \ AQ = 1.5 \, \text{cm}, \ AC = 4.5 \, \text{cm} \) Prove that \( \triangle APQ \sim \triangle ABC \).
Hence, find the length of \( PQ \), if \( BC = 3.6 \, \text{cm} \).