https://www.wolframalpha.com/input/?i=sqrt((earth+radius+%2B+1.80m)%5E2+-+earth+radius%5E2)
sqrt((earth radius + 1.80m)^2 - earth radius^2) - Wolfram|Alpha
earth radiussqrt180m2
https://www.wolframalpha.com/input/?i=Earth%20equatorial%20radius
Earth equatorial radius - Wolfram|Alpha
equatorial radiusearthwolframalpha