Find the ratio between the third proportional of 32 and 48 with the third proportional of 4 and 18.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 8 : 9 .
Third proportional of a and b is c such that a : b = b : c, so c = b2 ÷ a
For 32 and 48
c = 482 ÷ 32 = 2304 ÷ 32 = 72
For 4 and 18
c = 182 ÷ 4 = 324 ÷ 4 = 81
Required ratio = 72 : 81 = 8 : 9