What should I do I don’t understand

Answer:
∠MCD and ∠GCM are complementary
∠FGM and ∠MGC are complementary
∠MCD, ∠CDM and ∠DMC add up to 180°
Step-by-step explanation:
Complementary angles are two angles that add up to 90°.
The angles of a triangle add up to 180°