If in △ABC, AB = AC and ∠ACD = 125°, then ∠BAC is:
Answer & explanation
Correct answer: option 4
Here, \(\angle\)ACB + \(\angle\)ABC + \(\angle\)BAC = \({180}^\circ\)
= x + x + \(\angle\)BAC = 180
= \(\angle\)BAC = 180 - 2x
As, \(\angle\)ACD = exterior angle of triangle ABC
= \(\angle\)ACD = \(\angle\)BAC + \(\angle\)ACB
= 125 = 180 - 2x + x
= x = 55
\(\angle\)BAC = 180 - 2x = 180 - (2 x 55)
= 180 - 110 = 70
Therefore, \(\angle\)BAC is \({70}^\circ\).