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,...
Free Math Help
Free Math Help: Area Formulas
The resource consists of area formulas and diagrams for a square, rectangle, circle, triangle, and trapezoid.
Varsity Tutors
Varsity Tutors: Hotmath: Review: Area
Find a quick, concise explanation of area and the formulas for different shapes. An example is given to help you understand how find the area of a shape. The area formulas are listed for different types of shapes.
Science Struck
Science Struck: Cross Sectional Area of a Cylinder
Presents the formula and an example showing how to find the cross-sectional area of a cylinder. In this case, it is the same as the surface area for the circular faces.
Alabama Learning Exchange
Alex: Arc Lengths and Sector Areas
Students will work in cooperative groups to discover the relationships between arc length, central angle measure, and circumference. They will also discover the relationship between circle area, central angle measures, and sector area....
George Mason University
Area Formula Lab
In this set of worksheet activities, students will be guided to discover formulas for area of polygonal shapes and circles.
Vernet -Virtual Education Resources Network
Salon Hogar: Referencia Rapida De Formulas Geometricas
This site provides the user with a useful reference to different geometric forms, their elements, formulas, and areas. Entirely in Spanish.
Cuemath
Cuemath: Cylinder
Mini-lesson takes a look at the definition and shape of a cylinder, cylinder formula, cylinder volume, and cylinder surface area. Try your hand at the cylinder surface area calculator and interactive questions for better understanding.
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: The Area of a Circle
An investigative approach is given to exploring finding the area of a circle.
National Council of Teachers of Mathematics
The Math Forum: Cylinder Formulas
This site from the Math Forum defines both a circular cylinder and a right circular cylinder. Pictures of each are provided. Formulas are provided.
University of Cambridge
University of Cambridge: Nrich: The Pi Are Square
Use the formula given for the area of a circle and a square to solve this challenge. This one page website has the solution available for you.
Shmoop University
Shmoop: Basic Geometry: Area Formulas
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas, examples, and practice exercises are included.
Shmoop University
Shmoop: Basic Geometry: Area (Polygon, Triangle, Circle, Square)
The geometry resource investigates the area of polygons, triangles, circles, and squares. Formulas and examples are included.
Purple Math
Purplemath: Geometry Word Problems: Introduction
Introduces how to set up and solve simple geometric-figure word problems. Includes advice regarding formulas to memorize.
Math Words
Math Words: Right Circular Cylinder
Find a picture of a right circular cylinder here with the formulas for volume, total surface area, and lateral surface area. Site by MathWords.com.
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.
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.
Illustrative Mathematics
Illustrative Mathematics: 7.g Stained Glass
In this lesson plan, 7th graders use formulas for area and circumference to solve the word problem.
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...
Khan Academy
Khan Academy: Circumference and Rotations
Practice these problems with circumference and rotations.
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...
Alabama Learning Exchange
Alex: Figure It Out
This is an Internet-based (online) and group discussion lesson. Students will learn the formulas for surface area and volume of cylinders and cones. Students should have previously learned how to determine the area for a circle; however,...
Illustrative Mathematics
Illustrative Mathematics: 7.g Designs
In this lesson plan, 7th graders use the formula for circles to determine the area and perimeter.