4. Here you will chart the shortest flight path from Toronto to New Delhi by modelling Earth's surface SCR as a sphere. As you develop your model, you may need to look up basic information about Toronto, New Delhi, and Earth. You may need to make choices (e.g. units), state assumptions, or introduce constants. Regardless, you must explain your rationale. Do not simply write your answer with little to no explanation. (4a) Define the surface of Earth as a set S CR. (4b) Parametrize S in a way consistent with the geographical definitions of latitude and longitude. (4c) Give the coordinates of Toronto and New Delhi using your parametrization.