In Fig. 16.139, if ∠ ACB =40°, ∠ DPB =120°, find ∠ CBD .

Question

In Fig. 16.139, if &#x2220; ACB =40&#xB0;, &#x2220; DPB =120&#xB0;, find &#x2220; CBD .

Philoid · Accepted Answer

We have,

∠ACB = 40^o

∠DPB = 120^o

∠ADB = ∠ACB = 40^o (Angle on same segment)

In triangle PDB, by angle sum property

∠PDB + ∠PBD + ∠BPD = 180^o

40^o + ∠PBD + 120^o = 180^o

∠PBD = 20^o

Therefore,

∠CBD = 20^o