Question

Lakmini decided to measure the circumference of the Earth

using a very long tape measure. She held the tape measure
Im from the surface of the (perfectly spherical) Earth all the
way round. When she had finished her friend said that her
measurement gave too large an answer and suggested taking
off 6 m. Was her friend correct?
[Take the radius of the Earth to be 6400 km (if you need it).]

Answer 1

Explanation:

[tex]\Delta C=2\pi(r_2-r_1)\\ \\ \Delta C=2\pi(6400001-6400000)\\ \\ \Delta C=2\pi\\ \\ \Delta C\approx 6.283m\\ \\ \text{So taking off 6 meters is reasonable.}[/tex}