What are three ways police conduct has remained the same over the past century? (I will give brainlist)

What is the approximate circumference of the circle shown below? 12.2 cm

2/6 of be by to 2/6 is to 24/72 ?

Which of the following is not a challenge to instituting sound global environmental policies? a. most changes are inexpensive and easy to implement. b. elected leaders who support unpopular environmental issues often are not re-elected. c. economic considerations outweigh environmental ones in many societies. d. there is no way to enforce international environmental agreements.