Dick Blick Art Materials
Start with a Circle...
The Golden Ratio. The Divine Proportion. Yup. It's math and art blended into one colorful activity. Young artists combine colored tissue paper circles and parts of circles to create geometric patterns. As a bonus, kids get to figure out...
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...
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...
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...
EngageNY
Construct an Equilateral Triangle (part 2)
Triangles, triangles, and more triangles! In this second installment of a 36-part series, your young mathematicians explore two increasingly challenging constructions, requiring them to develop a way to construct three triangles that...
Mathematics Assessment Project
Sorting Equations of Circles 1
Round and round we go. Learners first complete a task on writing equations of circles. They then take part in a collaborative activity categorizing a set of equations for circles based on the radius and center.
Curated OER
Parts of the Circle
For this geometry skills worksheet, learners respond to 3 questions that require them to examine the part of circles and identify them as diameters, chords, radii, or centers.
Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Curated OER
Circle Graphs
In this circle graphs learning exercise, students solve and complete 8 different problems that include word problems referring to two different circle graphs shown. First, they follow the directions for each problem and complete the...
Mathematics Vision Project
Module 6: Congruence, Construction, and Proof
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...
Curated OER
Inscribing a Hexagon in a Circle
This activity is a follow-on activity to inscribing a square in a circle. The overall problem is more complex. It deals with geometric constructions, properties of triangles, and regular hexagons. The final part of the activity...
Curated OER
Inscribing a Square in a Circle
Inscribing a square in a circle brings up a number of interesting geometry topics including triangle congruence and how to prove a quadrilateral is a square. This activity is followed up by finding the area of the square and determining...
EngageNY
Construct an Equilateral Triangle (part 1)
Drawing circles isn't the only thing compasses are good for. In this first installment of a 36-part series, high schoolers learn how to draw equilateral triangles by investigating real-world situations, such as finding the location of a...
Curated OER
Pizza Fractions
Everyone loves pizza! Learners define fractions and use manipulatives to calculate fractions. Kids cut circles to represent various fractional parts of a pizza. Some accommodations are included.
EngageNY
Tangent Lines and the Tangent Function
Construct tangent lines and make the connection to tangent functions. An informative instructional activity reviews the geometry origins of the tangent function. Pupils use that information to determine how to construct a tangent to a...
Curated OER
Parachutes, Circles and Pi...Oh My!
Students explore different size circles to discover the relationship between diameter and circumference. In this circles and Pi lesson, students construct simple parachutes using circle patterns of varying sizes. Students predict the...
Curated OER
Making a Circle Graph of a Sample Budget
Students examine a sample budget and categorize the entries as a group. Then in small groups they convert budget category totals to percents and degrees to make a circle graph related to a sample budget.
Math Mammoth
Measuring Angles
The first of two pages displays various angles as the measure of degrees of a circular arc. An explanation is written, and learners are asked to model each by holding up two pencils as the rays. The second page provides instruction on...
Curated OER
Parts of the Circle
In this geometry skills learning exercise, students examine 3 labeled circles and identify the noted items as diameters, chords, radii, or centers.
Curated OER
Parts of a Circle
In this geometric shapes worksheet, students respond to questions that require them to identify chords, radii, diameters and centers of 4 circles.
Curated OER
Exploring Harmonic Conjugates
High schoolers investigate harmonic conjugates using Cabri Software or the Ti Calculator to analyze harmonics. They explore different angles measurements as they move their circles around and solve problems.
EngageNY
Copy and Bisect an Angle
More constructions! For this third installment of a 36-part series, learners watch a YouTube video on creating door trim to see how to bisect an angle. They then investigate how to copy an angle by ordering a given list of steps.
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.
Balanced Assessment
Oops! Glass Top
A short assessment asks participants to find the original radius required to replace a table top. The problem provides a hypothetical situation of having a segment of a broken glass table top. Pupils find the radius of the...