In the figure, 'DeltaABC' is congruent to 'DeltaADC'. If the square ABCD is dilated by a factor of 2 to form A'B'C'D', what is the ratio of the area of A'B'C'D' to the area of ABCD?

2:1

3:1

4:1

5:1

The square is dilated by a factor of 2 to form A'B'C'D'.

Which mean the new square sides will be twice as much as the old square.

Let the side length of the square ABCD = x

∴ The side length of the square A'B'C'D' = 2x

∵ The area of the square = (side length) ²

Area of ABCD = x²

Area of A'B'C'D' = (2x) ² = 4x²

∴ Area of A'B'C'D' : Area of ABCD = 4x² : x² = 4 : 1