Which of the following is the equation of a circle centered at the origin with a radius of one unit? a)x+y=1
b)x^2+y^2=1
c)y=x^2+1
d)y=x+1

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.