Q3 of 153 Page 166

The side BC of ΔABC has been increased on both sides as shown. If ∠ABD = 105° and ∠ACE = 110°, then find ∠A.

B = 180 – 105 (sum of linear pair of angles is 180)


= 75


C = 180 – 110 (sum of linear pair of angles is 180)


= 70


So, A = 180 – (B + C) (sum of angles of triangle is 180)


= 180 – (70 + 75)


= 35O


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