The radius of a smaller circle is half the length of the radius of a larger circle. The area of the larger circle is 20 square inches. What is the
approximate area of the smaller circle?
A 5 square inches
B. 10 square inches
C 12 square inches
D. 15 square inches

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.