Question

prove that "the sum of all interior angels of a triangle is 180°

Answer 1

heyy
ur ans is
given abc is a triangle
RTP:- angle A + , angle B+angle C= 180. ......

Answer 2

Draw triangle ABC on the top of it construct a line de passing through A.
Now, in triangle ABC name angel A as 1 and angel B as 2 and angel C as 3
NOW name angel DAB as 4 and angel EAC as 5 .


Now angel 4=1 reason linear pair similarly angle 5=1 but, angel 4=2 reason alternate interior angels, similarly angel 5=3
Now by euclid's axiom = things which are equal to the same things are equal to one another.
Therefore angel 1=2=3
That is angel A=B=C
If all the angels are equal then
A+B+C= 180
3A =180 (A=B=C)
A=60
NOW, 60+60+60=180
Hence proved