What is the ratio of the fourth proportional of 2, 5, 6 and the fourth proportional of 6, 8, 9?
Answer & explanation
Correct answer: option 4
Using direct formula for the fourth proportional,
d = \(\frac{b\; \times\; c}{a}\)
d₁ = \(\frac{5\; \times\; 6}{2}\) = 15
d₂ = \(\frac{8\; \times\; 9}{6}\) = 12
Thus, d₁ : d₂ = 15 : 12 = 5 : 4