Question

find square root of 90 by estimation method​

Answer 1

90=2×45

=2×9×5

=2×3×3×5

√90=√(2×3×3×5)

=3√(2×5)

=3√10

Answer 2

$\sqrt{90} \\ \\ 90 - 1 = 89 \\ 89 - 3 = 86 \\ 86 - 5 = 81 \\ 81 - 7 = 74 \\ 74 - 9 = 65 \\ 65 - 11 = 54 \\ 54 - 13 = 41 \\ 41 - 15 = 26 \\ 26 - 17 = 9$

Thus,

$\sqrt{90} = 9.48.......$