Mt. San Antonio Collage
Circles
Don't circle around the topic, but get right to the center with tons of practice regarding circles in geometry. The note-incorporated learning exercise provides guided practice through many topics such as central angles, inscribed...
Flipped Math
Unit 11 Review: Circles
Solve problems around a circle. Pupils watch a video that shows how to apply concepts about circles and related angles and segments to find solutions to word problems. Learners then review the different concepts from the unit in...
Flipped Math
Intercepted Arcs
Intercept the class's learning on circles. Pupils learn the relationship between intercepted arcs and inscribed angles. The scholars use that information to find the relationship of angles in an inscribed quadrilateral and an angle...
Radford University
Where Should We Sit?
Where's the best seat in the house? Given a diagram of a movie theater, pupils determine the best seats based on the viewing angle. They use inscribed angles to justify their choices.
Corbett Maths
Angles in the Same Segment – Proof
If angles intercept the same arc, the angles must be the same size. The quick video talks through the proof of showing the reason two inscribed angles that intersect the same arc have the same measurement. Pupils then create their own...
Mathematics Vision Project
Module 5: Circles A Geometric Perspective
Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...
Virginia Department of Education
Angles, Arcs, and Segments in Circles
Investigate relationships between angles, arcs, and segments in circles. Pupils use geometry software to discover the relationships between angles, arcs, and segments associated with circles. Class members use similar triangles to...
Mathed Up!
Circle Theorems
Explore theorems involving circles. Individuals watch a video that reviews the basic parts of a circle. They learn about circle theorems and compete a activity of problems that use these theorems — putting their skills to work right away!
West Contra Costa Unified School District
Arcs and Angles
Noah didn't construct this kind of arc. High school scholars first explore how angles can be formed in circles. They then learn relationships between angles and arcs by conducting an exploratory activity where they position and draw arcs...
Mathematics Assessment Project
Inscribing and Circumscribing Right Triangles
High schoolers attempt an assessment task requiring them to find the radii of inscribed and circumscribed circles of a right triangle with given dimensions. They then evaluate provided sample responses to consider how to improve their...
Willow Tree
Angle Sum Property of Triangles
All triangles have some things in common. Using these properties of triangles, learners find missing angle measures. Scholars use the Angle Sum Property and properties of special triangles throughout the lesson.
EngageNY
Geometry Module 5: End-of-Module Assessment
The lessons are complete. Learners take an end-of-module assessment in the last installment of a 23-part module. Questions contain multiple parts, each assessing different aspects of the module.
EngageNY
Ptolemy's Theorem
Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.
EngageNY
Cyclic Quadrilaterals
What does it mean for a quadrilateral to be cyclic? Mathematicians first learn what it means for a quadrilateral to be cyclic. They then investigate angle measures and area in such a quadrilateral.
EngageNY
The Inscribed Angle Alternate – A Tangent Angle
You know the Inscribed Angle Theorem and you know about tangent lines; now let's consider them together! Learners first explore angle measures when one of the rays of the angle is a tangent to a circle. They then apply their newfound...
EngageNY
Geometry Module 5: Mid-Module Assessment
How can you formally assess understanding of circle concepts? Pupils take a mid-module assessment containing five questions, each with multiple parts.
EngageNY
Unknown Angle Problems with Inscribed Angles in Circles
We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson then...
EngageNY
Inscribed Angle Theorem and Its Applications
Inscribed angles are central to the instructional activity. Young mathematicians build upon concepts learned in the previous instructional activity and formalize the Inscribed Angle Theorem relating inscribed and central angles. The...
EngageNY
The Angle Measure of an Arc
How do you find the measure of an arc? Learners first review relationships between central and inscribed angles. They then investigate the relationship between these angles and their intercepted arcs to extend the Inscribed Angle Theorem...
EngageNY
Experiments with Inscribed Angles
Right angles, acute angles, obtuse angles, central angles, inscribed angles: how many types of angles are there? Learners first investigate definitions of inscribed angles, central angles, and intercepted arcs. The majority of the lesson...
EngageNY
Thales’ Theorem
Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...
Illustrative Mathematics
Right Triangles Inscribed in Circles I
One of the basic properties of inscribed angles gets a triangle proof treatment in a short but detailed exercise. Leading directions take the learner through identifying characteristics of a circle and how they relate to angles and...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Curated OER
Cabri Jr. Inscribed Angles
Young scholars construct inscribed angles using Cabri Jr. They draw a circle on their graphing calculator, then construct an inscribed angle and measure its angle measures. Learners drag the inscribed angle around the circle. They make...