Answer:
40
Explanation:
Use this picture as a reference.
So, using remote angles theorem, which states that; the angle formed from the extension of a side in a triangle is equal to the sum of the two angles which it does not make contact with, within the triangle. One can conclude that :
m< BCD = m<B + m<A
substitute:
m<BCD = 80 + 25
Simplify:
m<BCD = 105
Since it is given that m< BCE is 50, then one has to subtract m<BCE from m<BCD to get m<ECD
m<BCD - m<BCE = m<ECD
Subsitute:
105 - 50 = m<ECD
Simplify:
55 = m<ECD
Using the sum of angles in a triangle, which states that the sum of all the angles in a triangle is 180 degrees, one can say that:
m<D + m<ECD + m<E = 180
Substitute:
85 + 55 + m<E = 180
Simplify, inverse operations:
140 + m<E = 180
-40 -140
m<E = 40