Answer:
The segment should be 36 centimeters long
Step-by-step explanation:
Let us use the ratio method to solve the question
∵ The original scale is 1 cm : 8 m
∵ In the original drawing, the length of a segment is 9 centimeters
→ By using the ratio method
→  cm   :  m
→  1      :  8
→  9     :  x
→ By using the cross multiplication
∵ 1 × x = 9 × 8
∴ x = 72 m
∴ The actual length of the segment is 72 m
∵ The new scale is 1 cm : 2 m
∵ The actual length of the segment is 72 m
→ By using the ratio method
→  cm   :  m
→  1      :  2
→  y      :  72
→ By using the cross multiplication
∵ y × 2 = 1 × 72
∴ 2y = 72
→ Divide both sides by 2 to find y
∴ y = 36
∴ The drawing length of the segment is 36 cm in the new scale
∴ The segment should be 36 centimeters long