Does anyone know how to find the surface area?

What is the rotational symmetry of a wheel

Solve each quadratic equation by factoring and using the zero product property. n^2 - 49 = 0

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?