# CCGPS CA 5.1.3 Example 3

- Topic:
- Congruence, Symmetry

Given the quadrilateral , the square , and the information that is the same distance from and , show that is symmetrical along .

- Recall the definition of line symmetry.
- Since
and , is a line of symmetry for where . has the same area as because they share a base and have equal height. , so . - We now know
is a line of symmetry for and is a line of symmetry for , so and quadrilateral is symmetrical along .