Question

The value of $(109{)}^2$ is _______.

• A. 11881
• B. 10881
• C. 11891
• D. 11880

Answer 1

The correct option is A

11881

$109=100+9$

Using the identity:
$(a+b{)}^2$= $(a{)}^2+2\times a\times b+(b{)}^2$,
$(100+9{)}^2=(100{)}^2+2\times 100\times 9+(9{)}^2$
$=10000+1800+81$
$=11881$