



 
Roger, My diagram shows the water in the reservoir when the height is $h$ meters. $ABC$ is an equilateral triangle and $D$ is the midpoint of $AB$ so that $r$ is the radius of the circular top of the water. What are the measure of the angles $CAD$ and $DCA?$ Write $r$ in terms of $h.$ The volume of water, $V$ is given by $\frac13 \pi r^2 h.$ Write $V$ as a function of $h$ and use the calculus you know to complete the problem. Write back if you need more assistance. Penny  


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