OML Search

Inscribed angles, radii, and chords


Videos and lessons to help High School students learn how to identify and describe relationships among inscribed angles, radii, and chords.

Topics include the relationship between central, inscribed, and circumscribed angles; inscribed angles on a diameter are right angles; the radius of a circle is perpendicular to the tangent where the radius intersects the circle.



Common Core: HSG-C.A.2



Introduction to Circles
This video introduces the features of circles including secant, secant line, chord, diameter, radius, tangent line, and intersecting circles.


Inscribed and Central Angles
Showing that an inscribed angle is half of a central angle that subtends the same arc.



Inscribed and Central Angles
Introduction to inscribed and central angles with a few examples.
Hypotenuse of right triangle inscribed in circle.


Inscribed and Central Angles in a Circle
An angle inscribed in a circle has half the angle measure of the corresponding central angle. Drag the vertices on the circle to change the angles. When you make DAC the diameter, angle E would be 90 degrees.



Example with tangent and radius.


Tangent Lines to a Circle Example Problems
This video provides example problems of determining unknown values using the properties of a tangent line to a circle.
Measure of circumscribed angle.


Inscribed and Circumscribed Polygons.

Try out our new and fun Fraction Concoction Game.

Add and subtract fractions to make exciting fraction concoctions following a recipe. There are four levels of difficulty: Easy, medium, hard and insane. Practice the basics of fraction addition and subtraction or challenge yourself with the insane level.

Fraction Concoction Game




OML Search


We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.