About 10°, depending on what kind of accuracy you'd like. https://en.wikipedia.org/wiki/Small-angle_approximation#Error_of_the_approximations https://en.wikipe

About 10°, depending on what kind of accuracy you'd like. https://en.wikipedia.org/wiki/Small-angle_approximation#Error_of_the_approximations https://en.wikipedia.org/wiki/Small-angle_approximation#Erro...