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Curated OER
Inscribed Angles
Students analyze inscribed angles and intercepted arcs and explore the relationships between the two. They investigate the properties of angles, arcs, chords, tangents, and secants to solve problems involving circles.
Khan Academy
Khan Academy: Area of a Sector
Relate the area of a sector to the area of a whole circle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Cuemath
Cuemath: Circles
Explore everything about circles. Learn various parts of a circle like a diameter, radius, circumference, circles chord, tangent circles, major arc, segment, sector, and discover other interesting aspects of it. Try your hand at solving...
CK-12 Foundation
Ck 12: Interactive Geometry: 8.10 Sector Area
Learn and understand the sector of a circle.
Oswego City School District
Regents Exam Prep Center: Circles: Area of Sectors and Segments
Material to supplement classroom instruction on sectors and segments of circles. Find guidelines on how to find the area of sectors and segments, as well as a multiple-choice quiz, and an activity idea called "Sectors and Pizza."
Math Words
Math Words: Sector of a Circle
This site offers a picture and short discussion of a sector of a circle. The site contains a link to the area of a sector of a circle in both degrees and radians. There are links to related words.
Math Is Fun
Math Is Fun: Circle Sector and Segment
Learn about the "two main 'slices' of a circle" called a sector and a segment, and see how you can calculate the area of a sector or segment using trigonometry.
Math2
Math2: Circles
This site has many useful formulas and examples relating to circles, including related definitions, circumference of a circle, area of a circle, length of a circular arc, area of a circular sector, equation of a circle in cartesian...
Mr. Martini's Classroom
Mr. Martini's Classroom: Circles Geometry Review
This resource provides two levels of multiple choice questions to review the parts of a circle as well as area and perimeter.
Illustrative Mathematics
Illustrative Mathematics: G C Mutually Tangent Circles
Three circles are mutually tangent. Students are asked to find the total area of the circles plus the area inside where they meet. Students will need to know how to calculate the area of a circle, a sector of a circle, and an equilateral...
Johan Claeys
Math Abundance: The Circle: Basic Concepts
Goes over the equation of a circle, parametric equations of a circle, intersection of circle and line, tangent line in a point of a circle, etc.
Sophia Learning
Sophia: Finding a Formula for the Surface Area of a Cone
This video tutorial demonstrates how to find the formula for the surface area of a cone.
CK-12 Foundation
Ck 12: Geometry: Area of Sectors and Segments
[Free Registration/Login may be required to access all resource tools.] In this lesson students find the area of a sector or segment. Students examine guided notes, review guided practice, watch instructional videos and attempt practice...
CK-12 Foundation
Ck 12: Area of Sectors and Segments: Pacman Area
[Free Registration/Login Required] Students are to determine the area of the shaded region between two radii. Click challenge me to answer practice questions and click learn more to watch a video.
CK-12 Foundation
Ck 12: Trigonometry: Area of a Sector
[Free Registration/Login may be required to access all resource tools.] Find the area of a sector of a circle.
CK-12 Foundation
Ck 12: Geometry: Area of a Circle
[Free Registration/Login may be required to access all resource tools.] In this lesson students calculate the area of circles and the area of sectors of circles by using given information and formulas. Students examine guided notes,...
Sophia Learning
Sophia: Sector Area of a Circle: Lesson 2
This lesson will demonstrate how to find the area and radius of a circle when given the sector area and central angle measure. It is 2 of 8 in the series titled "Sector Area of a Circle."
Sophia Learning
Sophia: Sector Area of a Circle: Lesson 4
This lesson will demonstrate how to find the area and radius of a circle when given the sector area and central angle measure. It is 4 of 8 in the series titled "Sector Area of a Circle."
CK-12 Foundation
Ck 12: Geometry: Circumference and Arc Length Study Guide
This study guide on circumference and arc length covers key vocabulary, the parts of a circle, and formulas for circumference, area, and arc length. It is available for download with free registration.
Math Is Fun
Math Is Fun: Definition of Circumference
Definition of circumference. Click the "here's more" link to learn more about a circle; its radius and diameter, area, lines, slices and common sectors.
Illustrative Mathematics
Illustrative Mathematics: G C, G Srt Setting Up Sprinklers
In this task, students must decide where to place sprinklers on a lawn so that the maximum area of the lawn will be watered. To solve it, they must find areas of sectors of circles and use trigonometric ratios to solve right triangles....
Curated OER
Circle Picture
This site provides definitions for different parts of a circle, pictures to more clearly represent formulas involving circles. Some of the formulas discussed include: area of a circle, area of a sector of a cirles, circumference, length...
Curated OER
Parametric Unit Circle
This site provides definitions for different parts of a circle, pictures to more clearly represent formulas involving circles. Some of the formulas discussed include: area of a circle, area of a sector of a cirles, circumference, length...