What value of x would make AOB a line in figure, if ∠AOC=4x and ∠BOC=(6x+30∘)?
If AOB is a line, then
∠AOB=180∘ ( a straight angle = 180∘)
⇒∠AOC+∠BOC=180∘
⇒4x+(6x+30∘)=180∘
⇒10x+30∘=180∘
⇒10x=150∘
⇒x=15∘