Mathematics

In ΔABC above, BC is produced to D, /AB/ = /AC/ and ∠BAC = 50o….

In ΔABC above, BC is produced to D, /AB/ = /AC/ and ∠BAC = 50o. Find ∠ACD
  • A.
    50o
  • B.
    60o
  • C.
    65o
  • D.
    100o
  • E.
    115o
Correct Answer: Option E
Explanation

ACB = ABC [Base angles of isoceles triangle]
ACB + ABC + 50o = 180o[sum of angles in a triangle]
ACB + ABC = 180o – 50o = 130o

ACB

130o/2

= 65o

ACD + ACB = 180o[sum of ∠s on a straight line]
ACD + 65o = 180o
ACD = 180o – 65o = 115o