00:02
Okay, this is problem 30.
00:09
We're asked to estimate the earth's circumference knowing information that they gathered over 2 ,000 years ago.
00:18
They have a picture drawn for you and it looks something like this.
00:25
So we have the center of the earth and we have a line coming out here and we're going to make this a for alexandra.
00:36
A is going to be alexandria.
00:46
We're going to make another line up here, and we're going to make this s.
00:51
S is going to be sine.
00:57
Okay, this is angle 1 here.
01:02
They said that they put a stick directly out.
01:08
Here's our stick.
01:12
And the sunlight's coming.
01:14
This is our sunlight.
01:15
Let me make this a different color.
01:19
It's hitting like this.
01:21
Now think about it, these are going to be parallel lines.
01:25
So this is our sunlight...