The vast geographical feature which forms a border between nigeria, chad, cameroon and niger, is a__

The Answer is Lake.
This Vast geographical feature is also called "Chad Lake". There is a vast area which forms a border between Nigeria, chad, Cameroon and Niger is a lake.
Chad is an Area with four bioclimatic zones and in the world it is one of the 48 land-locked countries. The second largest lake in the west Africa is Lake Chad.

3 notebooks and 3 pencils packages

step-by-step explanation:

((3×1.25)+(3×2.75))=12

3×1.25=3.75

3×2.75=8.25

3.75+8.25=$12