Item 4 the arch of the sydney harbor bridge in sydney, australia, can be modeled by y=−0.00211x2+1.06x, where x is the distance (in meters) from the left pylons and y is the height (in meters) of the arch above the water. item 4 the arch of the sydney harbor bridge in sydney, australia, can be modeled by y=−0.00211x2+1.06x, where x is the distance (in meters) from the left pylons and y is the height (in meters) of the arch above the water.