Find the ratio between the third proportional of 12 and 42 with the third proportional of 16 and 56.
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Correct answer: B
Explanation
The correct answer is option 2 i.e. 3 : 4.
Third proportional to 12 and 42 = (42²) / 12 = (42 × 42) / 12 = 1764 / 12 = 147
Third proportional to 16 and 56 = (56²) / 16 = (56 × 56) / 16 = 3136 / 16 = 196
Ratio = 147 : 196 = 3 : 4