The distance between two points P and Q is d and the length of their projections of PQ on the co-ordinate planes are \[{{d}_{1}},{{d}_{2}},{{d}_{3}}\]. Then \[d_{1}^{2}+d_{2}^{2}+d_{3}^{2}=k{{d}^{2}}\] where . k- is

The distance between two points P and Q is d and the length of their p

1.	The distance between two points P and Q is d and the length of their projections of PQ on the co-ordinate planes are \[{{d}_{1}},{{d}_{2}},{{d}_{3}}\]. Then \[d_{1}^{2}+d_{2}^{2}+d_{3}^{2}=k{{d}^{2}}\] where . k- is
A.	1
B.	5
C.	3
D.	2
Answer» E.

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The distance between two points P and Q is d and the length of their projections of PQ on the co-ordinate planes are \[{{d}_{1}},{{d}_{2}},{{d}_{3}}\]. Then \[d_{1}^{2}+d_{2}^{2}+d_{3}^{2}=k{{d}^{2}}\] where . k- is

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