Gudday all

I am doing some circular edging in my garden and want to determine how many bricks I would need (at least get close).

The brick edge is 76mm, the radius of the curve is 5,500mm. After rifling through my Uni text books I felt that using part of the method of exhaustion might give me the answer.

The equation is l = 2rsin(pi/n) where l = 76, r =5500 and n = no. of bricks (I hope that this is correct.)

Plugging in and simplying I get 6.91^10-3 = sin (pi/n).

Question: How do I rearrange to solve for n?

I have looked at this for a long time but Uni was such a long, long time ago.