







(3d) Whether line segment intersects triangle 
20190413 

rj pose la question : Well hello,
Lets say I have a triangle,
Not any ordinary triangle, but a triangle that is represented in 3 dimensions. I also have a line segment.
Lets say that this triangle has points A(0,0,0), B(1,0,0), C(0,1,1)
And the line segment has points D(0,1/2,0), E(1,1/2,1)
In what way can I find if the line segment and triangle intersect? Their intersection point?
I don't prefer matrices, because they don't make any sense, but ... if that's the only way to solve this, then do what's necessary.
Thank you in advance. Penny Nom lui répond. 





How can we draw the equation "x+y=1" in 3d? 
20130503 

shimaa pose la question : how can we draw the equation "x+y=1" in 3d Robert Dawson lui répond. 





Can a line segment curve over two planes? 
20100214 

Graham pose la question : I am working on a math fair project.
Can a line segment curve over two planes?
Such as, if I had a three dimensional L bracket and I drew a line segment
on it with a marker starting on the bottom of the L and had it curve
around the corner and up the top, would it still be considered one line
segment? Or is that two line segments?
Is there a rule that a line segment can only occupy one plane?
Thank you.
Graham Chris Fisher lui répond. 





The volume of 3D figures 
20090429 

Serena pose la question : What is the formula for finding the volume of 3D figures Robert Dawson lui répond. 





Drilling holes in a cube 
20061212 

Liz pose la question : What is the volume of the solid remaining if a unit cube has a hole drilled thru one face to the opposite side and the hole that is drilled is a cylinder of unit diameter. Then the cube is rotated and an identical hole is drilled from an untouched face to the opposite side. Then the cube is rotated and an identical hole is drilled between the last two untouched faces. This will result in the cube vertices and the remaining volume of the cube falling into 8 parts. What is the total volume of these 8 parts. How is this volume calculated? Penny Nom lui répond. 





Pythagoras in three dimensions 
20021014 

Miki pose la question : A room is 6m long, 5m wide and 3 m high. Find the distance from the corner of the floor to the opposite corner of the celing. Peny Nom lui répond. 

