Medal and fan for geometry help.
@welshfella
Find the area of the base. It's a regular hexagon.
The formula is \[\frac{ 3\sqrt{3} }{ 2 }*a^2\] ?
Okay, is 'a' 8.7 or 10 or something else?
10
I think that it is: \[\Large \begin{gathered} base\;area = \frac{{perimeter \times apothem}}{2} = \hfill \\ \hfill \\ = \frac{{\left( {10 \times 6} \right) \times 8.7}}{2} = ...? \hfill \\ \end{gathered} \]
261
ok! and the requested volume is: \[\Large \begin{gathered} volume = base\;area \times height = \hfill \\ \hfill \\ = 261 \times 7 = ...? \hfill \\ \end{gathered} \]
1827
that's right!
I didn't expect the previous formula to be similar to this figure.
yes! Such formulas are very similar each to other at a first sight
@Michele_Laino
here we have to compute the base area first, in order to do that, we can apply the Eron's formula: the half perimeter of the base triangle, is: \[\Large p = \frac{{10 + 8 + 6}}{2} = ...?\]
12
correct!
so the area of the base triangle, is: \[\Large \begin{gathered} area = \sqrt {p\left( {p - a} \right)\left( {p - b} \right)\left( {p - c} \right)} = \hfill \\ \hfill \\ = \sqrt {12 \times \left( {12 - 10} \right) \times \left( {12 - 8} \right) \times \left( {12 - 6} \right)} = ...? \hfill \\ \end{gathered} \]
576
ok! we have: \(area= \sqrt 576=24\) now the requested volume is: \[\Large volume = \frac{{24 \times 8}}{3} = ...?\]
64
that's right!
I'm very sorry I have to go out now
I never liked esoteric formulas. Just build the thing. One of the six triangles that makes the base: \(\dfrac{1}{2}\cdot (10\;ft)\cdot(8.7\;ft) = 43.5\;ft^{2}\) There are 6 of these: \(43.5\;ft^{2}\cdot 6 = 261\;ft^2\). This is the area of the base. \(261\;ft^{2}\cdot 7\;ft = 1827\;ft^{3}\) This is the volume.
here I am
that's right, the requested volume is \(64\)
the base area can be computed noting that the triangle is a right triangle, so we have: area=\((6 \times 8) /2=24\)
alright
:)
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