An oil rig is in the sea. A port is on the shoreline 500 m directly North of the oil rig. The shoreline is straight and runs from the East to the West. 2000 m East of the port is an oil refinery. A pipeline to carry oil from the rig must be built to the refinery. Building the pipeline costs $50 per meter if it is in the water and $20 per m if it is on land. Determine where the pipeline should make landfall in order to minimize cost. Include a labelled diagram for full marks. 4 marks