Question

Using identity find the value of $(7.2{)}^2$

Answer 1

$(7.2{)}^2$

$\Rightarrow (7+0.2{)}^2$

$\Rightarrow 7^2+(0.2{)}^2+2(0.2\left)\right(7)$

$\Rightarrow 49+0.04+\left(0.4\right)\left(7\right)$

$\Rightarrow 49.04+2.8$

$\Rightarrow 51.84$.