What is the ratio of the mean proportional between 4.5 and 0.5, and the third proportional to 4.5 and 9.0?
Answer & explanation
Correct answer: option 4
Mean proportion = \(\sqrt {4.5 x 0.5 }\)
⇒ \(\sqrt {2.25 }\) = \(\frac{15}{10}\) = \(\frac{3}{2}\)
The third proportional a,
⇒ 4.5 : 9.0 : a
⇒ 4.5a = 9 x 9
⇒ a = 18.
Ratio MP : Third proportional = \(\frac{3}{2}\) : 18 = 3 : 36 = 1 : 12.