EngageNY
Inscribed Angle Theorem and Its Applications
Inscribed angles are central to the lesson. Young mathematicians build upon concepts learned in the previous lesson and formalize the Inscribed Angle Theorem relating inscribed and central angles. The lesson then guides learners to prove...
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...
Illustrative Mathematics
Two Wheels and a Belt
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
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...
Texas Instraments
Angles in Circles
Teach your learners how to investigate the relationship between a central angle and an inscribed angle which subtend the same arc of a circle. The dynamic nature of Cabri Jr. provides opportunity for conjecture and verification.
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...
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 plan then...
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...
Curated OER
Length of an Arc and Area of a Sector
For this length of an arc and area of a sector worksheet, 10th graders solve and complete 12 different types of problems. First, they find the length of an arc in a circle with a given radius and central angle measure. Then, students...
EngageNY
Arc Length and Areas of Sectors
How do you find arc lengths and areas of sectors of circles? Young mathematicians investigate the relationship between the radius, central angle, and length of intercepted arc. They then learn how to determine the area of sectors of...
Texas Instruments
Cabri Jr. Inscribed and Central Angles
Learners will differentiate between inscribed and central angles in this geometry lesson. They answer questions dealing with circles as they relate to inscribed triangles and angles. This assignment includes a printable worksheet.
Virginia Department of Education
Arc Length and Area of a Sector
What do skateboarding and baked goods have in common with math? You can use them to connect half-pipe ramps and cakes to arcs and sectors. Pupils compare the lengths of three different ramp options of a skate park. They calculate the...
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...
Curated OER
Measurement of a Central Angle
Students calculate the measurement of a central angle. In this geometry lesson, students identify properties of circles. They use Cabri software to create and analyze graphs.
Curated OER
Positive and Negative Angles and Arcs
To better understand that the intersection point of two lines lies inside a circle, learners use their keen measurement skills. They discuss arcs, rays, tangent lines, and reflex angles. Then, they put their skills to work as they...
Curated OER
Area and Perimeter
Learners find the area and perimeter of regular polygons and composite figures and examine the effect on the area and perimeter of a figure if the dimensions are multiplied by a constant. The nine page worksheet contains thirty-seven...
Curated OER
Arc Measurement Based on The Measurement of a Central Angle
Students define keywords that are important to solve problems. In this geometry activity, students find the arc length and angle of a circle. They convert between radians and degrees.
Curated OER
Arc Length and Sectors
Find the length of an arc. Students relate central angles to the area and length of a sector and graph circles on the TI to make predictions.
Curated OER
Properties of Arcs, Lengths and Chords
Young scholars differentiate between the different properties of arcs, arc lengths, chords, and chord lengths. In this circles lesson, students calculate the arc length of a given circle, and find the measure of the inscribed angles of a...
Curated OER
Relationships Among Arc and Angle Measures in Circles
Learners follow the directions on the attached worksheet to construct shapes using Geometer's Sketchpad. To start the lesson, it is suggested that the teacher guide the students through the initial problem. When constructions are...
Curated OER
Circles and Angles
Students identify tangents, chords and secants. In this geometry activity, students graph circles and identify angles created by secant lines, tangent lines and chords.
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...
Curated OER
Finding the Area of Regular Polygons
Learners analyze relationship between the increase in polygons sides and a circle. In this geometry lesson, students relate the size of the central angle of a polygon, to a circle. They compare the formula for the area of a polygon and a...