GeoGebra Classroom

Inscribed Angle Theorem

Angle ABC is called an inscribed angle. Move point C around and see what happens to angle ABC. Then move points B around and see what happens to angle ABC

When moving point B does the angle change?

Select all that apply
• A
• B

When moving point C does the angle change?

Select all that apply
• A
• B

Now we will connect some more points and create a new angle ADC which is called the central angle

What do you think the central angle is in the circle shown above?

Play around with the positioning of points B and D. See if you can find a relationship between the inscribed angle and central angle

What kind of relationship did you notice between the central angle and the inscribed angle?

Review

The following are some problems for you to try

Find the measurement of the central angle

What is the measurement of the central angle

Select all that apply
• A
• B
• C
• D

Find the measurement of the inscribed angle

What is the measurement of the inscribed angle

Select all that apply
• A
• B
• C
• D

Find the measurement of the central angle

What is the measurement of the central angle

Select all that apply
• A
• B
• C
• D