1. Corresponding angles are the same (congruent).

for the polygons ABCD and KLMN

ABC=KLM, BCD=LMN, CDA=MNK and BAD=LKN

2. Corresponding sides are all in the same proportion

for the polygons ABCD and KLMN

AB/KL = BC/LM = CD/MN = DA/NK

3. Corresponding diagonals are in the same proportion. Their ratio is the same as the ratio of the sides.

for the polygons ABCD and KLMN

AC / KM = BD / LN = AB / KL...

4. Area ratio - The ratio of the areas of the two polygons is the square of the ratio of the sides.

Area of ABCD / Area of KLMN = (AB^2) / (KL^2)