Question

If one of the four angles formed by two intersecting lines is a right angle then show that each of the four angles is a right angle ?

Answer 1

Step-by-step explanation:

Let AB and CD be two lines Intersecting at O, such that, ∠AOD=90°.

Now, ∠AOD=∠COB=90° (Vertically opposite angles)

⟹∠AOD+∠DOB=180° (Angles on a straight line)

⟹90+∠DOB=180°

⟹∠DOB=180-90

⟹∠DOB=90°

Thus, all angles are 90°.