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The fourth proportional to 4, 9, and 12 is:
A24
B36
C27
D18
Answer & Solution
Correct answer: C. 27
1. Per OCR example: "Fourth Proportional to 4, 9 and 12: 4:9 :: 12:X, so 4X = 9×12, X = 27."
2. a:b :: c:d ⇒ ad = bc.
3. X = 108/4 = 27.
_Source: ICMAI BoS CMA Foundation Paper 3 (FBMS) — Paper3_07042026.pdf, Module 1 §1.1 (page 12)_