Question

The side BC of ΔABC has been produced to a point D, such that ∠ACD = 140. If ∠B = 2/5 × ∠A, then find ∠A.

Options...
A.) 90°
B.) 80°
C.) 110°
D.) 100°

Answer 1

A.) 90. Degree
B.) 80 dégrée

Answer 2

Answer:

∠BAC+∠ABC=∠ACD(Exterior angle sum property)

∠BAC+2/5∠BAC=140°

(5∠BAC+2∠BAC)/5=140°

7∠BAC/5=140°

7∠BAC=700°

∠BAC=700°/7

∠BAC=100°

Option D