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 .

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