Question

Using identities evaluate : ${102}^2$

Answer 1

${102}^2={(100+2)}^2$ is of the form ${(a+b)}^2=a^2+b^2+2ab$

where $a=100,b=2$

$\therefore {102}^2={(100+2)}^2$

$={100}^2+2^2+2\times 100\times 2$

$=10000+4+400=10404$