If an area is 78.5 yards what is that areas diameter

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81

The ph level of a blueberry is 3.1 what is the hydrogen-ion concentration [h+] for the blueberry