Answer: Bottom left corner
Angle DEC and Angle DEH
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Step-by-step explanation:
I recommend opening your favorite paint program, and using different colors to mark on the drawing as I have done below (see attached image). Note how angle DEC is in red and angle DEH is in blue. The two angles are adjacent, meaning they share the same ray (in this case, ray ED) and they form a straight angle.
Because they form a straight angle, or straight line, this means the two angles are supplementary. Supplementary angles always add to 180.