71.
The two numbers to each of which, or to the halves of which, unity is added, forming in every case a square number, are 48 and 1680.
72.
The true weight of a cheese that seemed to weigh 16 ℔s. in one scale of a balance with arms of unequal length, and only 9℔s. in the other, is 12℔. This is found by multiplying the 16 by the 9, and finding the square root of the result.
73.
The two parts into which 100 can be divided, so that if one of them is divided by the other the quotient is again exactly 100 are 991⁄101 and 100⁄101.