Parallelogram RSTU is shown below. Lian needs to prove that RS equals TU and RU equals TS. Which of the following reasons support one or more statements in the proof?
1) Corresponding parts of congruent triangles are congruent
2) Opposite sides of a parallelogram are congruent
3) Definition of a parallelogram
4) Symmetric property
5) Alternate interior angles are congruent
