 # 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.

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 the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.  