Question

Compute the square of 12.8

• A. 162.54
• B. 162.84
• C. 163.54
• D. 163.84

Answer 1

The correct option is D

163.84

$(12.8{)}^2$ can be written as

$(13-0.2{)}^2$

$=(13{)}^2+(0.2{)}^2-2\times 13\times 0.2\left[\right(x-y{)}^2=x^2+y^2-2xy]$

$=169+0.04-5.2$

$=163.84$