Place a cold pie in the oven and bake it for one hour.   So, get the pie out of the oven and let it be cool before eat.  Write a description of how the temperature of pie change in time.   Sketch a graphic of pie temperature as a  time function. [Stewart, 2003  p. 23]

The above exercise demand a graphic answer.  In iGraf, graphic answers are treated as discursive answers and, for this cause, the teacher will have to analyze it one by one.  The student can draw any graphic on the drawing area and proceed the send of solution... The teacher will receive the graphic (and the record of the student's session) and will be able to  analyze it, as in the visual aspect as by the strategy student used to draw.

If you suppose the answer below is good enough, send it.   Else, use the edition tool to alter the graphic and create a more realistic solution !