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How to calculate the volume of this shape?
I've tried to do $2.5\cdot 2.5\cdot 3.14\cdot 12$ and then divide that with $3$ since the first part is a cone. But I only get $78.5$ by doing that. Am I missing a part or what? I'm confused.
$\endgroup$ 121 Answer
$\begingroup$It must be an "ice-cream cone"
$$\underbrace{\dfrac{1}{3}\pi(2.5)^2\cdot\underbrace{\sqrt{12^2-2.5^2}}_{\text{height of cone}}}_{\text{cone part}} + \underbrace{\dfrac{1}{2}\cdot \dfrac{4}{3}\pi(2.5)^3}_{\text{semisphere}} \approx 109.54141$$
I only now noticed the new picture. In this picture the height of the cone is given as $12cm$. In this case it works out to about $111cm$. Did the question specify to round to the nearest $10cm$?
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