A certain planet travels around its star in a nearly circular orbit with a radius of 103 million miles. If it takes 1.06 years for the planet to complete one orbit,

Question

A certain planet travels around its star in a nearly circular orbit with a radius of 103 million miles. If it takes 1.06 years for the planet to complete one orbit, estimate the orbital speed of the planet in miles per hour

Answer 1

orbit = circumference = 2pir = 2pi(103) million miles

per 1.06 years = 1.06(365.25)(24) hours

speed in mph = 2pi(103,000,000)/1.06(365.25)(24)

let pi= 3.141593

use a calculator and simplify

for a less accurate estimate, round the numbers

= 618 million per 8000

= 49 thousand mph