Question

Two straight lines AB and CD cut each other at O. If ∠BOD = 63°, then ∠BOC =

Options

•  63°

• 117°

•  17°

• 153°

Answer 1

Let us draw the following diagram showing two lines AB and CD intersecting each other at a point O.

Let the required angle ∠BOC measures x°.

Also, ∠BOCand ∠BODform a linear pair. Therefore, their sum must be equal to 180°.

That is,

∠BOC +∠BOD = 180°

It is given that. ∠BOD = 63°Substituting, this value above, we get:

∠BOC +63° = 180°

∠BOC = 180° - 63°

∠BOC =117°