Mathematiques
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Inscribed Angle Calculator.
An inscribed angle is half the intercepted arc measure.
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Les résultats se mettent à jour pendant la saisie.
Results update automatically as you type.
Use Cases
Geometry Homework Help
Quickly verify your answers when solving problems involving circles, arcs, and inscribed angles.
Example: If the intercepted arc is 80°, the inscribed angle is 40°.
Teaching and Learning
Use as a demonstration tool to show the relationship between arcs and inscribed angles in a classroom or study session.
Example: Show that a 120° arc always gives a 60° inscribed angle.
Frequently Asked Questions
- What is an inscribed angle?
- An inscribed angle is an angle formed by two chords in a circle that share an endpoint on the circle. Its vertex lies on the circle, and it intercepts an arc between the other two endpoints.
- How do I use this calculator?
- Simply enter the measure of the intercepted arc in degrees. The calculator will compute the inscribed angle, which is half the measure of the intercepted arc.
- Why is the inscribed angle half the intercepted arc?
- This is a fundamental theorem in geometry: the measure of an inscribed angle is always half the measure of its intercepted arc. This holds for any inscribed angle in a circle.
Tips & Common Mistakes
Tips
- Ensure the intercepted arc is measured in degrees; if you have radians, convert to degrees first.
- Remember that the inscribed angle is always exactly half the intercepted arc, no matter the circle's size.
- For a semicircle (180° arc), the inscribed angle is always 90°, a right angle.
- Double-check your arc measurement: it should be the arc opposite the angle, not the adjacent arc.
Common Mistakes to Avoid
- Forgetting to divide the arc by 2, resulting in the angle being equal to the arc instead of half.
- Using the wrong arc: the intercepted arc is the one inside the angle, not the one outside.
- Entering the arc in radians but expecting the result in degrees without conversion.
Last updated: August 13, 2026