The second one because 1/4 times 3/3 equals 3/12
1.The second industrial revolution refers to the changes in manufacturing and building, and the new inventions brought about by the introduction of inexpensive steel. After the Second Industrial Revolution cites were overcrowded because of the need of jobs for people. The streets of cities were overcrowded which had sanitation issues so, lots of people were getting sick as a result. Crime grew as a result of not enough police and because it was easy to lose the police in crowds of people. Devices such as cars, electric lights, and telephones made the middle class's life more enjoyable. People who did urban planning reforms such as trolly parks made it so the working class could spend their extra time and money on something enjoyable.
2.One of the largest effects that we still deal with all over the war is Slavery. The Atlantic Slave Trade is a well-known trade route used to trade slaves and items through Africa.Through the trade and conquering of Africa by the Europeans, weapons and processed items were traded with the Africans.The trade of items allowed major groups to prosper and continue to grow. This eventually resulted in large African kings defending their lands against the powerful Europeans when they attacked.
3.Nationalism is patriotic feelings towards your country. Nationalism can cause terror or hate to other nations that you see as a threat to your way of life. I'll give you one example so as not to do the work for you. The Nazi's were a great example of strong nationalism.
If the rectangle has a fixed width of 300, it means that
where 
and 
are width and length, respetively.
So given the length , the are would be
