Question

Triangle ABC , the bisector f angle B and C intersect at I . If angle A= 70 find angle BIC​

Answer 1

angle A is 70

By angle sum property

angle ABC + angle ACB=180-70

=110... 1

a Bisector bisects an angle into 2 halfs therefore

a angle CBI is half of angle ABC... 2

and angle ICB is half of angle ACB... 3

multiplying 1 by half

1\2 angle ABC + 1\2 angle ACB=

1\2 × 110

angle CBI +angle ICB=55... from 2 & 3

By angle sum property

angle BIC =180-angle CBI +angle ICB

angle BIC =180-55

angle BIC=125