In a pyramid I have the side plans $25^{\circ}$ from vertical line. I will make a L-shaped support in the corners. In the CAD I can see it will be $100.29^{\circ}$ between the planes. How can calculate this with formulas? Could not attach picture in the system but I can seen separate.
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Take $z$ axis up, and the base of the pyramid aligned with the $x$ and $y$ axes. I think you mean that one side plane has a normal vector $n = (0, \cos(25{\rm deg}), \sin(25{\rm deg}))$, and an adjacent side plane has normal $m = (\cos(25{\rm deg}), 0,\sin(25{\rm deg}))$. Then the cosine of the angle between the normals is the dot product $$ n\cdot m = \sin^2(25{\rm deg}) = 0.17861 $$ and this is equal to (minus) the cosine of 100.29 degrees. The normals form an acute angle but your "L" fits inside, I assume, so is obtuse. |
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