${(a+b+c)}^2$ formula
Formula
${(a+b+c)}^2$ $=$ $a^2+b^2+c^2$ $+$ $2ab+2bc+2ca$
It is called $a+b+c$ whole square formula and read as $a$ plus $b$ plus $c$ whole square. It is mainly used to expand the square of sum of three terms in terms of them.
Proof
The $a+b+c$ whole square algebraic formula can be derived in two distinct mathematical approaches.
Algebraic Method
The expansion of $a+b+c$ whole square is derived in algebraic form by the multiplication of algebraic expressions.
Geometrical Method
On the basis of areas of square and rectangle, the $a$ plus $b$ plus $c$ whole square algebraic identity is derived in mathematical form geometrically.