Answer:

Step-by-step explanation:
we know that
The circumference of a circle is equal to

where
D is the diameter
in this problem we have

substitute
-----> equation that give the value of the circumference

Answer:
4:5
Step-by-step explanation:
half of 16 is 8, and half of 8 is 4
and half of 20 is 10, and half of 10 is 5
hope i helped man
The metric system is based on power os 10’s- brainest pls xx