What about some maximisation/minimisation problems? And finding areas and volumes of irregular shapes - the wine glass by rotation is a classic...
Borsuk-Ulam Theorem -- from Wolfram MathWorld
Using some calculus tools you can easily prove :
That at any given moment, there are two diametrically opposite points on the
(spherical?) Earth's surface where the temperatures are equal and the
barometric pressure are equal.
I do not understand why you would decide to do a presentation on something you know nothing about. Surely the point is either to present about something you do know, or to do some research (which no doubt is something whoever set you this task would have wanted you to do). It is not our job to do your research.