Question

Given that the Andromeda galaxy is about `163000` light years across and subtends about `4.1^@`, approximately how many light years away is it?

Answer 1

Approximately `2.3` million light years.

Explanation:

`4.1^@ = 4.1*pi/180 ~~ 1/14` radians

So the approximate distance to Andromeda is:

`163000*14 ~~ 2300000` light years