Answer:
Obtuse triangle
Step-by-step explanation:
Given are the vertices of a triangle
Let A (-4, 0, 0),B (0, 0, 0),C(7, 2, 6)
Let us find angles between AB, BC and CA
AB = (4, 0,0): BC = (7,2,6) : CA = (11, 2,6)
Cos B = [tex]\frac{AB.BC}{|AB||BC|} \\[/tex]
B = arc cos [tex]\frac{AB.BC}{|AB||BC|} \\[/tex]=137 deg 54 min 7 sec
Similarly
A=29 deg 53 min 53 seconds
C = 12 deg 12 min 3 sec
Obtuse triangle since one angle > 90 degrees
