What's the square root of 1/961 if you answer

Which geometric principle is used to justify the construction below?

Acarton of juice contains 64 ounces miss wilson bought six cartons of juice how many ounces of juice did she buy

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?