Teachers' Domain
Introduction to Angle Measure
An all-encompassing package provides video clips that demonstrate real-world activities that have to do with angles. After watching the Cyberchase cartoons, learners discuss why a "v" shape is used to measure a turn. A pair of vital...
Curated OER
The Circle's Measure
Listen to the story "Sir Cumference and the Dragon of Pi" and solve the riddle and to save Sir Cumference from the knights. Your students will love mixing an activity with story and will practice their measuring skills while...
Curated OER
Super Shapes Part 2 - Circles
Through the use of Internet, video, and hands-on activities, youngsters learn the parts and characteristics of a circle. This fantastic lesson has some excellent website activities included in the plan. Your kids will have a much greater...
Curated OER
The Circumference of a Circle and the Area of the Region it Encloses
Bring your math class around with this task. Learners simply identify parts of a given circle, compute its radius, and estimate the circumference and area. It is a strong scaffolding exercise in preparation for applying the formulas for...
Curated OER
Measures of Circular Motion
Physicists become Olympians in a competition using centripetal force. They ride a bicycle to comprehend relationships between linear and rotational motion. If you have an old-fashioned record player, it can be used to help pupils...
Texas Instruments
Drawing a Line Tangent to a Circle
Explore lines tangent to a circle. In this math lesson plan, students manipulate circles and lines on a TI calculator. They draw a circle and analyze perpendicular lines intersecting the circle in only one place. This activity...
Curated OER
Measuring the Area of a Circle
When mathematical errors happen, part of the learning is to figure out how it affects the rest of your calculations. The activity has your mathematicians solving for the area of a circular pipe and taking into consideration any errors...
EngageNY
Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams
First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a...
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...
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...
EngageNY
From Circle-ometry to Trigonometry
Can you use triangles to create a circle? Learners develop the unit circle using right triangle trigonometry. They then use the unit circle to evaluate common sine and cosine values.
EngageNY
Secant Lines; Secant Lines That Meet Inside a Circle
Young mathematicians identify different cases of intersecting secant lines. They then investigate the case where secant lines meet inside a circle.
Willow Tree
Circle Graphs
Pie isn't just for eating! Scholars learn to create pie charts and circle graphs to represent data. Given raw data, learners determine the percent of the whole for each category and then figure out the degree of the circle that percent...
Illustrative Mathematics
Seven Circles III
A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...
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 activity then...
Curated OER
Properties of Circles
Students study the properties of circles. In this circles lesson, students read a word problem about circles. Students watch a video about the activity and then practice drawing the circle solution to the problem. Students watch another...
Curated OER
Measuring Pumpkins and Our World
Students estimate the circumference of a pumpkin. They measure the pumpkin and other school objects, and record the measurements on worksheets.
Futures Channel
Folding Circles
Students investigate properties of circles. In this geometry lesson plan, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
Curated OER
Circles 1, 2, 3, 4
Here is a way to help your charges identify circles and spheres. In this shapes geometry and technology lesson plan, students identify and draw circles and explain the related attributes. They recognize circles and spheres while...
Curated OER
Lesson #10 Standard Measurement
Learners are introduced to units of measurement found on a ruler as well as what attributes make an object difficult or easier to measure with a ruler. The teacher has various objects placed around the room, and the youngsters practice...
Curated OER
Tree Measurement
Measure a tree? Yes, measure a tree! Students get outside and measure a tree's trunk, crown, and height. Each group compares their answers to determine if any re-measuring is necessary. Once back in the classroom, students make bar...
Curated OER
Measuring the Earth
Students use principles of geometry to measure the circumference of the Earth. In this applied geometry lesson, students use mathematics to determine scientific information. They make measurements, calculate the central angle, and...
Alabama Learning Exchange
Unit Circle: Special Angles—Just Know One
It's all about the patterns! Young scholars learn that the unit circle repeats itself in all four quadrants. Using these patterns, they evaluate the sine, cosine, and tangent of special angles.
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.