how to make a class project pyramid?

You can find some schematics here:

http://www.korthalsaltes.com/pyramid.htm

It is pretty good.

Is this a trick question? The Valley of the Kings has tombs, but no pyramids. However, there are several pyramids elsewhere in Egypt. Just choose another site. I'm not sure what details you want to include. If you just have to do the outside shape use lightweight building materials such as:

sheets of balsa wood, styrofoam, or carboard in pyramid shape, then spray one side at a time with adhesive and sprinkle on sand.

Sugar cubes are a time honored building material, especially if you are making the step pyramids. They do not work well for smooth sided pyramids , unless you are a good builder.

If you are doing three pyramids, you may want to move to display board, plywood, or heavy cardboard as a base. A regular poster board bends under weight.

Do your research well, I am not an expert on pyramids , but I do know that not all pyramids are made entirely of sandstone. Some are topped with limestone, which will have a smoother texture and possibly a different color.

If you have to make a replica of the inside of the pyramid, good luck, I hope you have patience! Use a hinge attached to the inside of a pyramid so that it can be folded back to show the inside.

The enchanted learning link below actually has a pattern to make pyramids from paper. One side folds down so that you can see inside the pyramid.

The second site focuses on in the Valley of the Kings. It includes information on the 100 + TOMBS in the valley. Photos included.Hope this helps.