Solve Isosceles Triangle in Coordinate System

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Homework Help Overview

The discussion revolves around determining the possible locations of point R in an isosceles triangle PQR, given points P(3,3) and Q(4,4) within a coordinate system constrained to the first quadrant. The problem involves integer coordinates and the geometric properties of triangles.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore the number of possible integer-coordinate points for R that would maintain the isosceles property of triangle PQR. There are discussions about the implications of the distance between P and Q not being an integer and the use of the perpendicular bisector of PQ.

Discussion Status

Participants have offered various counts of potential points for R, with some suggesting infinite possibilities while others refine the criteria to integer coordinates. The conversation reflects differing interpretations of the problem's constraints and the geometric relationships involved.

Contextual Notes

There is a noted requirement for R to have integer components, and the distance between points P and Q complicates the assumptions about possible solutions. The discussion also touches on the geometric paths R could trace, including lines and circles, which may involve non-integer values.

thereddevils
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Homework Statement



I will to explain this without a diagram. Consider a coordinate system(1st quadrant) where the x and y-axis both stop at 7 units (i mean the boundary), there are two points P(3,3) and Q(4,4). How many points can R be positioned such that PQR is an isosceles triangle.

Homework Equations





The Attempt at a Solution



I got 6.
 
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Well I had quite a few and started counting them... Eventually I counted up to infinite different possible points :-p

There are actually 3 paths the point R can trace, a line and 2 circles. See if you can find them.
 
thereddevils said:

Homework Statement



I will to explain this without a diagram. Consider a coordinate system(1st quadrant) where the x and y-axis both stop at 7 units (i mean the boundary), there are two points P(3,3) and Q(4,4). How many points can R be positioned such that PQR is an isosceles triangle.

Homework Equations





The Attempt at a Solution



I got 6.
Then you haven't given all the information. Are you talking about a "mesh" where the points must have integer components? As you give it, any point on the perpendicular bisector of PQ works and there are an infinite number of them.
 
HallsofIvy said:
Then you haven't given all the information. Are you talking about a "mesh" where the points must have integer components? As you give it, any point on the perpendicular bisector of PQ works and there are an infinite number of them.

yeah sorry, it must be of integer components where you can precisely represent that particular point on the plane.

My 6 points are

(5,2) , (2,5) , (6,1) , (1,6) , (7,0) , (0,7)
 
thereddevils said:
must be of integer components where you can precisely represent that particular point on the plane.

Yet the distance between P and Q is not an integer.
Anyway, this means we have the two equations

[tex]\sqrt{(x-4)^2+(y-4)^2}=n[/tex]

[tex]\sqrt{(x-3)^2+(y-3)^2}=n[/tex]

where n is an integer, to solve simultaneously.
After simplifying, we find the perpendicular bisector of PQ to be the line x+y-7=0
Now just use all possible integer values of x and y such that x+y=7.

I don't know if I should scrap the idea of the point R can trace that are circles rather than this line, because that means we have to use a non-integer value for another length.
 
Mentallic said:
Yet the distance between P and Q is not an integer.
Anyway, this means we have the two equations

[tex]\sqrt{(x-4)^2+(y-4)^2}=n[/tex]

[tex]\sqrt{(x-3)^2+(y-3)^2}=n[/tex]

where n is an integer, to solve simultaneously.
After simplifying, we find the perpendicular bisector of PQ to be the line x+y-7=0
Now just use all possible integer values of x and y such that x+y=7.

I don't know if I should scrap the idea of the point R can trace that are circles rather than this line, because that means we have to use a non-integer value for another length.

sigh.. 8 points then including (4,3) , (3,4)
 

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