Question

to verify experimentally that if two line intersect then Verticall opposite angleare equal

Answer 1

to prove angle 1 equal to angle 3


you know that angle 1 + Angle 2 equal to 180 degree. give this equation 1

second we know that angle 2 + angle 3 equal to 180 degree give this equation 2

comparing equation 1 and 2

angle 1 + angle 2 equal to angle 2 + angle 3

implies that angle 1 equal to angle 3