Evaluate $(9.8)^{2}$ by using the identity $(a - b)^{2} = a^{2} - 2 a b + b^{2}$ .

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Solution

Using the given identity $(a - b)^{2} = a^{2} - 2 a b + b^{2}$ to evaluate $(9.8)^{2}$
We can write $(9.8)^{2}$ = $(10 - 0.2)^{2}$
$∴$ $(10 - 0.2)^{2}$ = $10^{2} - 2 (10) (0.2) + {0.2}^{2}$ $=$ $100 - 4 + 0.04$
Hence the answer is $96.04$

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