Question

In the given figure, AOB is a straight line. If ∠AOC + ∠BOD = 85°, then ∠COD =

(a) 85°

(b) 90°

(c) 95°

(d) 100°

Answer 1

It is given that is a straight line.

Also,,and form a linear pair.

Therefore, their sum must be supplementary.

That is

...(i)

It is given that

$\angle AOC+\angle BOD=85°$ ...(ii)

On substituting the value of (ii) in (i) we get,

$$\begin{gathered} \angle COD+85°=180° \\ \Rightarrow \angle COD=180°-85° \\ \Rightarrow \angle COD=95° \end{gathered}$$
Hence, (c) is the correct option.