Answer:
Explanation:
AB = BC
=> Triangle ABC is an Isosceles Triangle
Thus, Angle C = Angle A
DE = BE
=> Triangle DEB is an Isosceles Triangle
Thus, Angle D = Angle B
Proof that triangle ABC and DEB are similar:
Angle DBE = Angle A (corresponding angle)
Angle BDE = Angle C (Both Triangle are Isosceles, if one pair of the angle are equal then the other pair should also be equal)
=> Triangle ABC ~ Triangle DEB (AA)
Therefore, Angle E = Angle B
Find angle B:
Angle C + Angle A + Angle B = 180
40 + 40 + angle B = 180
Angle B = 180 - 80
Angle B = 100 degree
But Angle B = Angle E = 100 degree
Therefore, Angle E = 100 degree
