_To Find the Square of a Number_, set the cursor to the number on D and
read the required square on A under the cursor. The rule for
_The Number of Digits in a Square_ is easily deducible from the rule for
multiplication. If the square is read on the _left_ scale of A, it will
contain _twice_ the number of digits in the original number _less_ 1; if
it is read on the _right_ scale of A, it will contain _twice_ the number
of digits in the original number.
EX.—Find the square of 114.
Placing the cursor to 114 on D, it is seen that the coinciding number
on A is 13. As the result is read off on the _left_ scale of A, the
number of digits will be (3 × 2) − 1 = 5, and the answer is read as
13,000. The true result is 12,996.
EX.—Find the square of 0·0093.
The cursor being placed to 93 on D, the number on A is found to be
865. The result is read on the _right_ scale of A, so the number of
digits = −2 × 2 = −4, and the answer is read as 0·0000865
[0·00008649].
_Square Root._—The foregoing rules suggest the method of procedure in
the inverse operation of extracting the square root of a given number,
which will be found on the D scale opposite the number on the A scale.
It is necessary to observe, however, that if the number consists of an
_odd_ number of digits, it is to be taken on the _left-hand_ portion of
the A scale, and the number of digits in the root = (N + 1)/(2), N being
the number of digits in the original number. When there is an even
number of digits in the number, it is to be taken on the _right-hand_
portion of the A scale, and the root contains _one-half_ the number of
digits in the original number.
EX.—Find the square root of 36,500.
As there is an _odd_ number of digits, placing the cursor to 365 on
the L.H. A scale gives 191 on D. By the rule there are (N + 1)/(2) =
(5 + 1)/(2) = 3 digits in the required root, which is therefore read
as 191 [191·05].