Answer:
Second choice.
Step-by-step explanation:
Set the compass to the radius of the circle because the sides of the hexagon are equal to the radius.
256 * 40 = 10,240 cm needed
so if the balls are 30 cm each then
10, 240 divided by 30 = 341.3
so the teacher will need 342 balls.
It helps because when you subtract 4 from 10 all you have to do is add 20