An office building is built in the shape of a four-sided pyramid. It stands 820 feet tall and is 180 feet wide at its base. Imagine that a coordinate grid is placed over a side of the building. In the coordinate grid,
each unit represents one foot. Enter an absolute value function whose graph is the V-shaped outline of
the sides of the building. Take one comer of the building to be the origin of the coordinate grid and
express your answer using
improper fractions in simplest form where needed.

y =_?