00:01
So here's a really interesting problem that has this reason conceptually about rate.
00:05
So since this is a circle, we know the area of a circle is pi r squared.
00:09
And what help me solve this problem is just make a table.
00:11
So let's say at day zero, which is before anything changes, we need a radius.
00:18
And we're not told the initial radius, so let's just assume it's one.
00:22
Then the area of the circle, pi one squared would just be pi, right? okay, so now let's have things change.
00:30
We're told that the rate of the radius changes at two kilometers per day.
00:34
So on the next day, we'll go up by two...