State with reasons that angle ACB is bisected by line OC

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Discussion Overview

The discussion revolves around the geometric problem of proving that angle ACB is bisected by line OC, with a focus on the construction of a circle tangent to line AB and the relationships between various points and angles in the configuration.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants assert that AB is 6 cm and that the circle should be tangent to AB.
  • One participant mentions that AB = AC since they are tangents drawn from point A to the circle, leading to the conclusion that angles ABC and ACB are equal.
  • Another participant questions how to prove that line OC bisects angle ACB, expressing doubt about the construction.
  • A participant introduces a scenario involving point X outside the circle and points of tangency Y and Z, asking what can be inferred about triangles XY and XZ in relation to the circle.
  • One participant suggests that the relation being sought is generally true and encourages others to make necessary corrections and apply hints provided earlier.
  • A later reply discusses the congruence of triangles formed by the radius of the circle and the tangent line, suggesting this as a reason for the bisection of angle ACB.

Areas of Agreement / Disagreement

Participants express uncertainty about the construction and whether line OC indeed bisects angle ACB. There are multiple viewpoints regarding the correctness of the construction and the generality of the relationship being discussed.

Contextual Notes

Some assumptions about the construction and the properties of tangents and angles are not fully resolved, leading to varying interpretations of the problem.

mathlearn
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Here is the Problem

View attachment 6180

Here is the construction, Hoping that I have done it correct "State with reasons that $\angle$ ACB is bisected by line OC"

View attachment 6181

Many THanks (Party)
 

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Last edited:
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AB is given as 6 cm and the circle should be tangent to AB.
 
greg1313 said:
AB is given as 6 cm and the circle should be tangent to AB.

Yes I updated the diagram correcting that error :) As AB = AC as they are tangents drawn to the circle from external point A. $\therefore \angle{ABC}=\angle{ACB}$

But still how can it be proved that
State with reasons that $\angle {ACB}$ is bisected by line OC"
 
Let $X$ be any point outside of a circle $C$. Let the points $Y$, $Z$ be the points of tangency at the circle $C$ and the lines $XY$ and $XZ$. What can be said about triangles $XYC$ and $XZC$ ?
 
mathlearn said:
Here is the Problem
Here is the construction, Hoping that I have done it correct "State with reasons that $\angle$ ACB is bisected by line OC"
Many THanks (Party)

greg1313 said:
Let $X$ be any point outside of a circle $C$. Let the points $Y$, $Z$ be the points of tangency at the circle $C$ and the lines $XY$ and $XZ$. What can be said about triangles $XYC$ and $XZC$ ?

Thanks but I doubt whether the Line $OC$ bisects angle $ACB$ which is really inside the triangle ? (Thinking) Have I done the construction wrong? Is the type of the circle correct?
 
See post #2.

The relation that is to be found is true in general, which is what I was trying to get at in post #4. Make the necessary corrections and apply the hints I gave to state your answer (with reasons).
 
greg1313 said:
See post #2.

The relation that is to be found is true in general, which is what I was trying to get at in post #4. Make the necessary corrections and apply the hints I gave to state your answer (with reasons).
View attachment 6185

Many THanks :)
 

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:D Thank you very much , I was struggling a long here for around a day or two

The sides was produced in the other direction

And Greg I think the reason for the bisection is the congruence of those two triangles due to the radius of the circle at the tangent and the common line CD and the 90 degree angle formed at the tangent line and the radius

Many THanks (Smile)
 
  • #10
That's correct. Good work! :)
 

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