Apolygon that has all sides the same measure and all angles the same is called?

the answer is b.

64

step-by-step explanation:

c=2πr=2·π·8≈64

answer: 4  

the square root of 16 is 4. it is a very simple mathematic concept. a square root when a number multiplied by itself will result in a number. here, the number 16 comes when 4 is multiplied by 4. hence the square root of 16 is 4. you can always figure out a square root by the inverse operation of squaring.