you're an architect.. you're supposed to think and come up with solutions.  How will draw details, think of design solutions, structural issues etc if you can't even make a hemisphere out of modelling board?  xD

here *borrows you my brain*

please,im just a  new student,student....i just need help.

if you're not after a very smooth surface, you can look up the geodesic dome

http://hilaroad.com/camp/projects/dome/dome.html

if you're after a smoother surface you can always increase the number of triangulations

this is a throw-away assignment that won't even end up in your portfolio.   just come up with something and move on.  they'll tell you what you did wrong.  it's school, you are allowed to make mistakes.  it's how you learn shit.

build it up out of contour rings.

remember: The importance of school is to try things yourself and try to come up with solutions.  It doesn't matter if you get it right or not.

Do a web search of "flattened world globe". You will see the way that maps are projected onto flat surfaces which are then meant to be applied over spherical solids.

Obviously, you will not care about the map image, but the ways you can create a series of connected "tapered lozenges" to form a sphere (or hemisphere) may be inspirational.