Normally calculating a square root without a calculator is a bitch.
This morning I looked up what an acre was and found it was an unwieldy figure of 4840 square yards and wondered what that actually meant. I created a method for calculating the approximate value of a square root. The method is easier to show than if I just explain it.
4840 1
484 10
121 40
This number is easy to work with 40 is a third of 120
120 / 3/2= 80 40 x 3/2 = 60
80+60= 140. 140 / 2 = 70 correct
I tested this with 6750
Here the last digit is helpful for dividing the number
665 / 5 = 135 (6 x 20 (hundred / five) = 120 + 15)
135 50
Seven divides almost exactly into 50 and exactly into 135 to create a ratio of 19:7
19 - 7 = 12
135 / 19/12 50 x 19/12
=85 5/19 =76 1/6
Totals added divided by two = over 80. Actual figure about 82.
