Which expression gives the surface area of a sphere with radius r? A. 4 pi r^2
В. 4 pi r^3
C. 4/3 pi r^2
D. 4/3 pi r^3​

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f