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Square root and Cubic root

12 Sep

Hi, how are you going mate?
Do you know how to solve this equation by estimation method ?

for square root

estimation method say 10 X 10 = 100 ….20 x 20 = 400 …. 30 X 30 = 900
625 is between root 20 and 30 …625 is ended by 5 only the multification of 5


60 x 60 = 3600
70 x 70 = 4900
4489 is between 60 and 70 4489 is ended by 9, therefore it could be 3 or 7
63 X 63 = 3969
and 67 x 67 = 4489

solution for cubic root is similar


10 x 10 x 10 = 1 000
20 x 20 x 20 = 8 000

so 5832 is between cubic root of 10 and 20
now look at the last number of 5832 is ended by 2 is only multification of 8
how 8 x 8 x 8 = 2 … 8 x 8 = 64 take 4
4 x 8 = 32 so it is 2
our estimation is 18


30 x 30 x 30 = 27 000
40 x 40 x 40 = 64 000

therefore 42875 is between cubic root 30 and 40
so our estimation is 35

have a good day

Problem Set

1. Find the square root of the following number
a. 14 400 b. 168 000 c. 64 000 000 d. 2025

2. Find the cube root of the following number
a. 1728 b. 4096 c. 8000

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