Step-by-step explanation:
<u>Method</u><u> </u><u>1</u><u>:</u>
Given that:
78 : 120 :: ? : 66
Here,
Product of extremes = 78 and 66
Product of means = 120 and ?
so,
(78*66) = (120 * ?)
⇛5148 = 120 * ?
⇛5148 = 120?
⇛120? = 5148
Shift the number 120 from LHS to RHS, changing it's sign.
⇛? = 5148/120
Therefore, (?) = 42.9
<u>Method</u><u> </u><u>2</u><u>:</u>
78 : 120 :: ? : 66
Convert each ratio into fraction.
⇛78/120 = ?/66
On applying cross multiplication then
since, (a/b) = (c/d) ⇛cd = ad
Where, a = 78, b = 120, c = ? and d = 66
Now,
⇛(120)? = (78)66
⇛120? = 5148
⇛(?) = 5148/120
Therefore, (?) = 42.9
<u>Ans</u><u>w</u><u>er:</u> Hence the value of (?) for the given problem is 42.9.
<u>Verification</u><u>:</u>
Check whether the value of (?) is true or false.
78 : 120 :: ? : 66
Substitute the value of (?).
⇛78:120 = 42.9:66
Product of extremes should be equal to product of means.
Product of extremes:- 78*66 = 5148
Product of means:- 120*42.9 = 5148
⇛5148 = 5148
LHS = RHS
Hence, verified.
