If every dimension of a two-dimensional figure is multiplied by k, by what quantity is the area multiplied?

For example: Square has dimension a

A = a² and if every dimension is multiplied by k new dimension would be:

A 1 = k² a² = k² A.

Or the area of rhombus: A = d1 * d 2 / 2

New area is: A 1 = k d 1 * k d 2 / 2 = k² A

Answer: If every dimension of two-dimensional figure is multiplied by k, the area is multiplied by k².