9, 18, 54, 216, ?, 6480

Answer: 1080

Explanation: Each term is obtained by multiplying the previous term by an increasing integer.

• 9 × 2 = 18

• 18 × 3 = 54

• 54 × 4 = 216

• 216 × 5 = 1080 (missing term)

Verification: 1080 × 6 = 6480, which matches the given next term.