Distance from a chord to the center of a circle

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The distance from the chord to the center of the circle is defined as the length of the perpendicular from the center of the circle to the chord.
Theorems on the distance from the center of the circle:

  1. Chords that are equal to each other are equidistant from the center of the circle.
  2. If in a circle, the distance of a chord from the center of the circle is less than the distance of another chord from the center of the circle, we can determine that the chord with the lesser distance is longer than the other chord.

All theorems can also exist in reverse.

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Distance from the chord to the center of the circle

We already know what a chord in a circle is and of course we know what the center of the circle means.
But, have you thought about the distance between the center of the circle and the chord?
That's exactly why we're here! We will introduce you to the theorems about the distance of the chord from the center of the circle that you can use without needing to prove them.
The theorems about the distance of the chord from the center of the circle make sense, there's no reason not to understand them and remember them naturally.

First of all, it's important to know:

The distance of the chord from the center of the circle is defined for us as the length of the perpendicular line that goes from the center of the circle to the chord.
That is:

Shall we start?


The chords that are equal to each other are equidistant from the center of the circle.

Let's see this in the illustration:

We will mark AA as the center of the circle

If 
BC=DEBC=DE
Then
AF=AGAF=AG

This theorem also works in reverse and therefore
if the distance of the chords from the center of the circle is equal, the chords are equal to each other.
Therefore:
If
AF=AGAF=AG
Then
BC=DEBC=DE

If in a circle, the distance of a chord from the center of the circle is less than the distance of another chord from the center of the circle, we can determine that the chord with the shorter distance is longer than the other chord.

This theorem can be a bit confusing.
To remember:
shorter distance - longer chord.
longer distance - shorter chord.

The truth is that you really don't have to memorize this sentence because you will see it beautifully in the illustration.
Let's see:

In front of us is a circle.
We will mark - AA as the center of the circle.
We can clearly see that the chord BCBC is shorter than the chord EDED.
We can also observe that for the shorter chord BCBC, the distance is greater from the center of the circle
and rather to the longer chord EDED, shorter distance than the distance from the circle.
According to this theorem we can say that:
if
AF<AGAF<AG
Then
BD<EDBD<ED
This theorem also works in reverse, so we can also say that:
if
BD<EDBD<ED
Then 
AF<AGAF<AG


If you are interested in this article, you might also be interested in the following articles:

  • The center of the circle
  • Circle
  • Radius
  • Diameter
  • Pi
  • The circumference perimeter
  • Circular area
  • Arcs in a circle
  • Chords in a circle
  • Central angle in a circle
  • Inscribed angle in a circle

In the Tutorela blog, you will find a variety of articles about mathematics.


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