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

Question

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

Philoid · Accepted Answer

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)

= 35^O