Quote by armolinasf
I feel like i've worked this one out every which way and I'm not seeing a relationship where i get something that is equivalent to the h*r^2 in terms of theta, unless that's where I'm going wrong?

You aren't going to find an expression purely in terms of theta. You'll need to use the fixed radius R as well. You've already got one relationship. r/h=tan(theta). That let's you get rid of one variable. You just need one more. What have you found?