Final answer:
When two quadrilaterals are similar, their corresponding angles are equal and their corresponding sides are proportional.
Step-by-step explanation:
When two quadrilaterals are similar, it means that their corresponding angles are equal and their corresponding sides are proportional.
So, in this case, if quadrilateral KLMN is similar to quadrilateral OPQR, it means that angle K is equal to angle O, angle L is equal to angle P, angle M is equal to angle Q, and angle N is equal to angle R. Additionally, the ratio of the lengths of the corresponding sides should be the same.
Therefore, if the length of side KL is x in quadrilateral KLMN, then the length of side OP should be 3x, since AB = 3x.