Help I need to get this done I have 15 questions

Answer:
8 cm
Step-by-step explanation:
(See the image attached for details)
Solve:
? + 7 = 15
Subtract 7 on both sides:
? + 7 = 15
-7 -7
? = 8 cm
Therefore, the yellow segment, or the missing side length, measures 8 cm.