TITLE: Tiling of regular polygon by rhombuses
QUESTION [5 upvotes]: A regular decagon and a regular dodecagon have been tiled with rhombuses. In each case, the sides of the rhombuses are the
same length as the sides of the regular polygon.
How many rhombuses will be there in a tiling by rhombuses of a $2002$-gon?
$A) 2002$ 
$B) 500 × 1001$ 
$C) 1000 × 1001$ 
$D) 1000 × 2002$
Could someone share please share the thought process of this question? I am not able to initiate it.

REPLY [4 votes]: This is not an answer but a hint.
(No alternate way to place a figure.)
Look at the labelization I have done of your figures: how many rhombii do you have with the same label ? Generalize... by thinking to a certain arithmetic progression.