Why not tubuh?
You can use "tubuh", though "badan" is more common in this context.
"Tubuh" is not accepted as an answer. Why not? What is the difference?
Can we say "di sentimeter" instead of "dalam sentimeter"?
No. For measurement units, we use "dalam".
Apa bisa juga pake kata dengan?
No, just "dalam".
dia mau mengukur badannya di dalam sentimeter