In ΔABC, side BC has produced to D. If ∠ACD = 132° and ∠A = 54�

1.	In ΔABC, side BC has produced to D. If ∠ACD = 132° and ∠A = 54°, then ∠B =?(a) 48o (b) 78o (c) 68o (d) 58o
Answer» (b) 78^o Because, Consider the ΔABC, We know that the exterior angle of a triangle is equal to the sum of its interior opposite angles. ∴ ∠ABC + ∠BAC = ∠ACD = ∠ABC + 54^o = 132^o = ∠ABC = 132^o – 54^o = ∠ABC = 78^o

In ΔABC, side BC has produced to D. If ∠ACD = 132° and ∠A = 54°, then ∠B =?(a) 48o (b) 78o (c) 68o (d) 58o

Answer»

(b) 78^o

Because,

Consider the ΔABC,

We know that the exterior angle of a triangle is equal to the sum of its interior opposite angles.

∴ ∠ABC + ∠BAC = ∠ACD

= ∠ABC + 54^o = 132^o

= ∠ABC = 132^o – 54^o

= ∠ABC = 78^o