I would use grams, because in my country watermelons are small, but if they were huge I would use kilograms
Step-by-step explanation:
to calculate circumference:

if the diameter is 16 then the radius would be 8.

to calculate the area of a circle:

Answer:
0.0009
Step-by-step explanation:
How to Write Out Number 0.0009 in Words: nine ten-thousandths