A spherical cell has a radius of 2.75 x 10 m. Use the formula for the surface area of a sphere S. A. = 4*3.14*r^2 to find the surface area of a cell.

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?