Help!!!What is Exercises 18 to 22???

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square

Prove that 16^4-2^13-4^5 is divisible by 11.

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?