Tenth graders explore the anatomy of circles — radii, chords, and arcs — and the angle relationships within them, discovering that a central angle equals its arc while an inscribed angle is exactly half.
Students will be able to…
A circle looks simple — but it’s full of hidden relationships. How do the angles, arcs, and chords inside a circle connect to each other?
Project this and tap each part of a circle. Have students learn how central and inscribed angles relate to arcs!
Tap any phase to open the teacher moves and student actions.
A circle looks simple — but what relationships hide inside?
Teacher models.
Class uses the Circle Explorer.
Students find measures.
One circle.
Aligned to the Common Core State Standards for Mathematics (High School Geometry).
Identify and describe relationships among inscribed angles, radii, and chords.
Prove that all circles are similar.
Find arc lengths and areas of sectors.
Know precise definitions of geometric figures.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students find the area of a sector and the length of an arc using the central angle as a fraction of the whole circle. A printable circles sheet is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.