Question

Using identity find the value of $(4.7{)}^2$.

Answer 1

$(4.7{)}^2$

$\Rightarrow (4+0.7{)}^2$

$\Rightarrow (4{)}^2+(0.7{)}^2+2\left(0.7\right)\left(4\right)$ $\left(\right(a+b{)}^2=a^2+b^2+2ab)$

$\Rightarrow 16+0.49+5.6$

$\Rightarrow 21.6+0.49$

$\Rightarrow 22.09$