We know d theta, let me do this in yellow. We know d theta, dt, is equal to 0.2 radians per minute. Now, what are we trying to figure out? Well, we're trying to figure out the rate at which the height of the balloon is changing. So if you call this distance right over here, this distance right over here, h, what we wanna figure out is dh dt. That's what we don't know. So what we'd wanna come up with is a relationship between dh dt, d theta dt, and maybe theta if we need it.