Question
Question: If the coordinates of point A, B, C are (–1, 3, 2), (2, 3, 5) and (3, 5, –2) respectively then ang...
If the coordinates of point A, B, C are (–1, 3, 2),
(2, 3, 5) and (3, 5, –2) respectively then angle A is
A
00
B
450
C
600
D
900
Answer
900
Explanation
Solution
D.R's of AB are 3, 0, 3
D.R's of AC are 4, 2, –4
\ cos A = 9+916+4+16(3)(4)+(0)(2)+3(−4)
cos A = 0
\ ŠA = 900