1. The problem statement, all variables and given/known data 2. Relevant equations Volume for cylinder = Pi (r)2 h Optimise : 1. make the best or most effective use of (a situation, opportunity, or resource). 2. rearrange or rewrite (data, software, etc.) to improve efficiency of retrieval or processing. 3. The attempt at a solution So I know that the Radius is 5, which means it has a diameter of 10. What i don't understand is how can you find the height with out knowing the volume?? If I get the volume I can apply it to this new formula to find the height: H = v / pi(r)2. I may have misunderstood the question or the meaning of optimise, which is my fault but if you do manage to help me out then THANKS ALOT.