Prisms and tetrahedrons

Q. What is the formula for volume of a tetrahedron whose vertices are given by the vectors a, b, c, d

Q. How to decide whether a system of planes can form a prism or not?

4 Answers

1
Che ·

i guess if i m rem correctly

volume=\frac{1}{6}\left [ \vec{b}-\vec{a} \; \;\; \; \vec{c}-\vec{a} \; \;\; \; \vec{d}-\vec{a}\right ]

a system of planes can form a prism only wen none of any two pair of planes out of them r parallel to each oder

62
Lokesh Verma ·

The proof for the expression given in Q 1 is as simple as this...

The volume is given by 1/6 (Area of base) x (Height)

Area of the base is the cross product of the two sides of the base..

while the perpendicular height can by found by using the dot product of the area vector with any of the other sides.

I hope that makes the expression given in #2 clearer..

106
Asish Mahapatra ·

The volume is given by 1/6 (Area of base) x (Height)

how ?

106
Asish Mahapatra ·

i always thot it was 1/3 (area of base) x (height)

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