It is the side of the triangle that is opposite of the right angle.
Total land mass of Europe is 10 million square kilometers.
The question is tricky since there is no natural border between Europe and Asia, which makes the calculation of the exact are problematic - so the number is actually arbitrary and approximate.
The five charactieristics are:
1.More than five million square feet of office space has to be present.
2.Over 600,000 square feet of retail space. has to be present.
3.The civillians will rise at morning and drop at afternoon.
4.The place is known as a single end destination,with all the facilities like recreation,transport,residential built within.
5.The area must look modern- not anything like a "city" 30 years ago.
Hope it helps!
Waves are created by winds blowing toward the coast, I think that is your answer
