# Measuring an Arc in Degrees

**URL:** <https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442>\
**Category:** Questions\
**Created:** [December 10, 2025, 2:02pm UTC](https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442 "2025-12-10T14:02:48Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Tracy\_Thomson](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/tracy_thomson/32/9298_2.png) [@Tracy\_Thomson](https://cl.desmos.com/u/Tracy_Thomson)\
**Post date:** [December 10, 2025, 2:02pm UTC](https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442/1 "2025-12-10T14:02:48Z")

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I am trying to figure out how to how to measure an arc (in degrees) on Desmos? I want to label the green arc to show my students an interactive version of Tangent-Chord Angle Theorem so show that the angle is half of the green arc it opens up to.

Thank you!

> **[Tangent Chord Theorem Circles](https://www.desmos.com/geometry/jurm0bzzbv)**
>
> Explore math with our beautiful, free online graphing calculator. Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more.

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**Author:** ![Daniel\_Grubbs](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/daniel_grubbs/32/719_2.png) [@Daniel\_Grubbs](https://cl.desmos.com/u/Daniel_Grubbs)\
**Post date:** [December 18, 2025, 5:45pm UTC](https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442/2 "2025-12-18T17:45:54Z")

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I used a `directedAngle` instead of a standard angle for the central angle, then a little finagling to get the arc measure:

[https://www.desmos.com/geometry/57j0lakkpm](https://www.desmos.com/geometry/rx7ka9mqpp)

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<div class="post-metadata">

**Author:** ![Tracy\_Thomson](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/tracy_thomson/32/9298_2.png) [@Tracy\_Thomson](https://cl.desmos.com/u/Tracy_Thomson)\
**Post date:** [December 18, 2025, 7:22pm UTC](https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442/3 "2025-12-18T19:22:38Z")

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THank you so much! This is perfect

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/desmos/original/2X/f/f5bd144684474e9a2f333002cde9840e52c5dbd3.png) [@system](https://cl.desmos.com/u/system)\
**Post date:** [December 20, 2025, 7:23pm UTC](https://cl.desmos.com/t/measuring-an-arc-in-degrees/8442/4 "2025-12-20T19:23:35Z")

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