Question

prove that the sum of all angles round a point is equal to 360degree

Answer 1

because,each angle=90 degree so four angle =90+90+90+90=360

Answer 2

Answer:

The proof is explained step-wise below :

Step-by-step explanation:

Let AB & CD be lines intersecting at O.

Now, Sum of two angles forming a linear pair is supplementary.

⇒ m∠AOC + ∠AOD = 180°  .........(1)

Also, m∠BOC + m∠BOD = 180° ..........(2)

Adding the equations,

m∠AOC + ∠AOD + m∠BOC + m∠BOD = 180° + 180°  

                                                                = 360°

Therefore, all angles around O sum up to 360°

Hence Proved.