Answer:

Step-by-step explanation:
Getting the central area of a polygon is not possible. Probably the question refers to the central angle. In a a regular polygon, getting the central angle is that you need to use the formula.
Central Angle of a polygon = 360 degrees / number of sides of a polygon.
Why 360 degrees? Because, a circle has a total of 360 degrees. And a circle is a polygon with no sides.
30 adults because if there are 3/10 it means they reduced so if the denominator is 100 then 30/100 is the answer :)
Since prime numbers only have two factors (itself and 1) then it would have to be the same number. So it would be the number besides one. Ex. Prime number: 7, the GCF would be 7 if it was compared with itself.