Question

I is the incentre of triangle abc what is angle bic

Answer 1

Angle ABI = Angle IBC = x Angle ACI = Angle ICB = y A + 2x + 2y = 180  2x + 2y = 180 - A x + y = 90 - A/2 In triangle BIC Angle IBC = x Angle ICB = y Angle BIC = 180 - (x + y) From 1st equation, Angle BIC = 180 - (90 - A/2=) Angle BIC = 90 + A/2  Hope this helps! :)