Question

Suppose the radius of the Earth is given to be 6378.01 km. Express the circumference of the Earth in m with 5 significant figures.
Round to 5 sig figs with trailing zeros --> 40074000

Answer 1

The mathematical description that fits to find the circumference of a circle (Approximation we will make to the earth considering it Uniform) is,

$\phi = 2\pi r$

Here,

r = Radius

The radius of the earth is 6378.01 km or 6378010m

Replacing we have that the circumference of the Earth is

$\phi = 2\pi (6378010m)$

$\phi = 40074000 m$

$\phi = 40074*10^3 m$

Therefore the circumference of the Earth in m with 5 significant figures is $40074*10^3 m$ and using only trailing zeros the answer will be $40074000m$