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\lhead{Bob Backstrom}
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\rhead{Newsletter Notes}
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We know that the lengths of the sides of a right angle triangle are related by
Pythagoras' Theorem. So we have:
$$(r + h)^2 = r^2 + d^2$$
And by rearranging to solve for d, we get:
$$d = \sqrt{2rh + h^2}$$
Everyone knows their height, and the internet knows the radius of the Earth,
so everything on the right-hand side is ready to go. Let's try it out.
Suppose you're 1.5 m tall, and standing at sea level --- this means you're
about 6,371 km, or 6,371,000 m, from the center of the Earth.
Then
$$d = \sqrt{2 \times 6371000 \times1.5 + 1.5^2} = 4371.8419...$$
So the horizon is 4,371.8 m or 4.4 km away!
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