Practicing Success
If in △ABC, AB = AC and ∠ACD = 125°, then ∠BAC is: |
75° 55° 60° 70° |
70° |
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 \({70}^\circ\). |