1 ∠ AOB = 60, so the triangle OCD is an equilateral triangle and the sector OCD is a circle of 1/6, so the area of ABCD is1/6 * π * 8 * 8-1/6 * π * 2 * 2.

2.CD=OD=8m, so the passing time is 8/4=2S, and the speed affected by skills becomes 2m/s, so the passing time is 8/2=4S, which is 100% more than before.

The damage of 3.4 seconds is 4× 700+760+700×116% = 4372, which can't be killed. Let x attack and kill, 700x+760+700x16% = 765438.