How can a man in America determine the direction of the Qiblah, knowing that the Earth is spherical and his head will be facing the sky and not the Kaaba?

Shaykh Muhammad Salih Al-Munajjid mentioned that Shaykh Ibn Uthaymeen issued a fatwa stating that a worshiper should not consider the curvature and sphericity of the earth's surface when determining the Qiblah. Rather, one should determine the direction towards Makkah by a straight line.