Question
Mathematics Question on introduction to three dimensional geometry
The points (1,3,4),(−1,6,10),(−7,4,7) and (−5,1,1)
A
form a rectangle which is not a square
B
form a rhombus which is not a square
C
form a parallelogram which is not a rhombus
D
are collinear
Answer
form a rhombus which is not a square
Explanation
Solution
Given points are A(1,3,4),B(−1,6,10),C(−7,4,7) and D(−5,1,1). AB=(−1−1)2+(6−3)2+(10−4)2
=(−2)2+(3)2+(6)2
=4+9+36=49=7 BC=(−7+1)2+(4−6)2+(7−10)2
=(−6)2+(−2)2+(−3)2
=36+4+9=49=7 CD=(−5+7)2+(1−4)2+(1−7)2
=(2)2+(−3)2+(−6)2
=4+9+36=7 AD=(−5−1)2+(1−3)2+(1−4)2
=(−6)2+(−2)2+(−3)2
=36+4+9=7 AC=(−7−1)2+(4−3)2+(7−4)2
=(−8)2+(1)2+(3)2
=64+1+9=74 BD=(−5+1)2+(1−6)2+(1−10)2
=(−4)2+(−5)2+(−9)2
=16+25+81=112 Since, sides AB=BC=CD=AD=7 and diagonals, AC=BD So, given points form a rhombus which is not a square.