For the first question, you will need to use similar triangle to help you solve the answer.
Let's say r is the radius and h is the height. Then you will need to use similar triangle to write r in term of h (like comparing two fractions).
Then you need to derive the volume equation in terms of h.
Then you will probably need to plug in the h that you found when is half volume.
You will need to use sin function to derive.
Since sin t = opp/hyp
t is your angle
opp is the height
hyp is the ladder which is constant
Hope this help
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