Solution:-
(i) We have to prove that, ∆ACO ~ ∆BDO.
So, from the figure
Consider ∆ACO and ∆BDO
Then,
∠AOC = ∠BOD [from vertically opposite angles]
∠A = ∠B
Therefore, ∆ACO = ∆BDO
Given, BD = 2.4 cm, OD = 4 cm, OB = 3.2 cm, AC = 3.6 cm,
∆ACO ~ ∆BOD
So, AO/OB = CO/OD = AC/BD
Consider AC/BD = AO/OB
3.6/2.4 = AO/3.2
AO = (3.6 × 3.2)/2.4
AO = 4.8 cm
Now, consider AC/BD = CO/OD
3.6/2.4 = CO/4
CO = (3.6 × 4)/2.4
CO = 6 cm