Answer:
The true statements regarding the diagram of triangle EBC are that ∆DEC is an exterior angle, ∆ABE and ∆EBC are supplementary angles, and ∆BCF and ∆DEC are supplementary angles.
Step-by-step explanation:
Based on the information provided, we can infer that the question is asking about the properties of exterior and interior angles of a triangle and their relationships. In triangle geometry, an exterior angle is equal to the sum of the two remote interior angles. Meanwhile, a linear pair of angles, such as one formed by extending one side of a triangle, consist of a pair of supplementary angles which add up to 180 degrees.
Given this understanding, let's evaluate the options:
A. ∆BEC is an exterior angle. (False, ∆BEC is actually an interior angle of the triangle.)
B. ∆DEC is an exterior angle. (True, this is formed by extending side BE through D.)
C. ∆ABE and ∆EBC are supplementary angles. (True, because they form a linear pair.)
D. ∆BCF and ∆DEC are supplementary angles. (True, since ∆BCF is an exterior angle and ∆DEC is a remote interior angle, and together with angle EBC, they sum to 180 degrees.)
E. ∆BEC is a remote interior angle to exterior ∆BCF. (False, ∆BEC is adjacent to ∆BCF making it not remote.)
Therefore, the true statements regarding the diagram of ∆EBC are B, C, and D.