In the given figure, straight lines PQ and RS intersect at O. If the magnitude of θ is 3 times that of ϕ, then ∠ϕ is equal to:
30°
40°
45°
60°
θ+ϕ=180∘
Since, θ=3ϕ
⇒ 3ϕ+ϕ=180∘
⇒ 4ϕ=180∘
⇒ ϕ=45∘
Hence, ∠ϕ=45∘