How did you calculate this?
Summer solstice in the northern hemisphere, there is a moment where there are no shadow. This is a fact and you can't say the contrary. At the same time and same longitude, everybody can mesure :
1-The angle formes by the shadow, by putting a book vertically and everyting and mesuring the angle with the shadow, when you have a triangle with a 90° angle).
2-You can approximatively say how far you are for the equator.
I invite you to make a little drawing of this, with a round earth and with a flat earth.
With that, you can mesure the earth diameter if it is round, and also the distance to the sun, if it is flat.
That's how made Eratosthene, some centuries before J-C. He found a diameter of 15000, which is not far from the real value. He hadn't any instrument to mesure the real distance beween Alexandria and the equator or to mesure the angle perfectly. Now we have all this technology and progress, every body can do this experience by himself
