So this is changing, changing, changing at 0.2 radians per minute. Now, my question to you, or the question that you're trying to figure out as you watch this hot air balloon is how fast is it rising right now? How fast is it rising just as the angle between the horizontal and kind of the line between you and the hot air balloon is pi over four radians, and that angle is changing at 0.2 radians per minute? So let's think about what we know and what we're trying to figure out. So we know a couple of things. We know that theta is equal to pi over four. If we call theta the angle right over here.