How would i write 81,900 in scientific notation?

East black horse $0.25 total budget is $555 it'll cost $115 for other supplies about how many flyers do you think we can buy

Use stokes' theorem to evaluate c f · dr where c is oriented counterclockwise as viewed from above. f(x, y, z) = xyi + 5zj + 7yk, c is the curve of intersection of the plane x + z = 8 and the cylinder x2 + y2 = 81.

Iknow the square root of 2 is irrational