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Suppose Eratosthenes had found that, in Alexandria, at noon on the first day of summer, the line to the Sun makes an angle 30° with the vertical. What, then, would he have found for Earth’s circumference?

Respuesta :

Answer:

6000 miles

Explanation:

The angle of the sun shone at an angle of 30° to the zenith

This means that the angle of the sector of the circle is 30° (θ)

S = Length of the sector of the circle = 500 miles (Distance between Alexandria and Syene)

r = radius of earth

Converting 30° to radians

[tex]\theta=30\times\frac{\pi}{180}[/tex]

[tex]S=r\theta\\\Rightarrow r=\frac{S}{\theta}\\\Rightarrow r=\frac{500}{30\times\frac{\pi}{180}}\\\Rightarrow r=954.93\ Miles[/tex]

Circumference

[tex]C=2\pi r\\\Rightarrow C=2\pi \frac{500}{30\times\frac{\pi}{180}}\\\Rightarrow C=6000\ Miles[/tex]

∴ Earth’s circumference would have been 6000 miles