given a triangle ABC whose angles are A=40 degree, B=95 degree and side b=30cm. Find the lenght of the bisector of angle C?
Find the lenght of the bisector of angle C?
geometry blows
Reply:In triangle ABC
m%26lt;A = 40
m%26lt;B = 95
m%26lt;C = 180 -(95+40) = 45
let CD bisects angle C
in triangle ACD
A = 40 deg
ACD = 45/2 = 22.5
ADC = 180-(40+22.5) = 180 -62.5 = 117.5 deg
apply sine rule to triangle ACD
a/sinA = b/sinB = c/SinC
AC/sin ADC = CD/sin A
b/sin 117.5 = CD/sin40
but b = 30
30/sin117.5 = CD/sin40
CD = 30(sin 40/sin 117.5)
30(0.6427)/0.8870
= 21.74 cm
The length of angle bisector C is 21.74 cm
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