Cutting the cone at various angles gives you various shapes of ellipse. Until the angle of your cut exceeds the angle of the side of the cone.

从侧面不同角度切割圆锥，你便会得到不同的椭圆，直到你的切割角度超过圆锥体侧边的角度。

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So as long as the angle of the cut comes shortof the angle of the cone's side it is an ellipse.

所以，只要你切割的角度达不到圆锥侧边的角度，它依然是椭圆。

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When we rotate this side here, but the Angle doesn't stay at a right Angle.

当旋转这个边时，这个角就不再是直角了。

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But the visitors really should have been level before the hour when Blackman's cross found Danny Kedwell, only for the Dons' top-scorer to side foot over the bar from the angle of the six-yard box.

BBC: Sammy Moore

Click on through for a side-angle conception.

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Dindane was denied by the legs of Craig Gordon, Jamie O'Hara almost went through on goal and Diop lashed into the side-netting from an acute angle.

BBC: Portsmouth 1-1 Sunderland