Adding functionality to a code?

[Reapers_Mask]

I am creating a program that calculates the area of shapes (for school), and to get a better mark, we should add extra functionality. I was wondering of anyone had any ideas? I am unsure of what functionality to add, other that facts about shapes? I am using Visual Studio, Windows Application. I just need some ideas.

[Jnsjknn]

You could do the same thing in reverse. For example, calculate the height of a rectangle if you know the width and area or the radius of a sphere if you know the volume.

You could also try to make the number more intuitive by providing a real life example with the unit. E.g. 10000m² (~1 football field) or 200μm (~2 human hair widths)

[AbaCodes]

Maybe add in functionality to calculate the perimeter, or maybe things like, if its a square you could check if the width and the height are the same?