Answer:
(A)60
(B)Triangle Proportionality theorem
(C)100
Explanation:
Triangle Proportionality theorem
If a line parallel to one side of a triangle intersects the other two sides of the triangle, then the line divides these two sides proportionally.
By this theorem, In the given triangle ABC,
|BC|=|EB|+|CE|
=60+40
|BC|=100 Units
Therefore:
The measure of EB is 60 units by the Triangle Proportionality theorem. Thus, BC must measure 100 units.