Q30 of 153 Page 148

In ΔABC, side BC is produced to D. If ∠ABC = 40° and ∠ACD = 120°, then ∠A = ?

ACD + ACB = 180 (Linear pair of angles)

ACB = 60^o

ABC = 40^o

As we know that

ACB + ACB + BAC = 180^o

BAC = 180 – 60 – 40

=80^o

In ΔABC, if ∠A + ∠B = 125° and ∠A + ∠C = 113°, then ∠A = ?

In ΔABC, if ∠A – ∠B = 42° and ∠B – ∠C = 21°, then ∠B = ?

Side BC of ΔABC has been produced to D on left hand side and to E on right hand side such that ∠ABD = 125° and ∠ACE = 130°. Then ∠A = ?

In the given figure, ∠BAC = 30°, ∠ABC = 50° and ∠CDE = 40°. Then ∠AED = ?