The curvature of the football field ⇐ General

[Anonymous]

I decided to calculate the curvature of a football field. Those. when the field is leveled by a laser level, and the Earth is round

This means that the center of the field should be lower than the edges. I figured it out in my head - it turned out to be 2-3 cm! This water will flow into the center. And now I calculated on a calculator using cosine

Determined how many kilometers are in one degree. I divided the circumference of the Earth into 360 degrees: 40,000/360 = approximately 111 km.
I determined the angle of a football field, from the edge to the center: 0.06 km/111, then took its cosine.
Well, I multiplied the cosine at 6,300,000 m (radius of the Earth). I got a 0.3 mm depression

Have you made a mistake anywhere?