Question 1203348
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I'll go over the basic outline of four approaches.


For each approach
A = (2,350)
B = (5,200)
C = (6,150)


Approach 1: 
Find slopes of line AB and line BC. 
If the slopes are equal, then the 3 points fall on the same line (to make them collinear). 
As optional practice you can find the slope of line AC, but it's not required. 


Approach 2:
Determine the equation of line AB and call this function f.
If f(6) = 150, then C is also on line AB to make the 3 points collinear.


Approach 3:
Focus on the x coordinates to see that because 2 < 5 < 6, it must mean B is horizontally between A and C.
This in turn then would mean AB+BC = AC if and only if A,B,C are on the same line together.
Use the distance formula to calculate the lengths of AB, BC, and AC.


Approach 4: 
Use the distance formula to calculate the lengths of AB, BC, and AC. 
Afterward, use Heron's formula to find the area of triangle ABC. 
If area = 0 then the points are collinear because we have a degenerate triangle aka a straight line.
If area > 0 then the points are not collinear because an actual triangle forms.
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