BBC
Bbc: Circumference and Area of a Circle
This is where you can pick up some valuable pointers on how to find the circumference and area of a circle. There is also information on how to find the perimeter and area of a semicircle. When you finish working your way through the...
Purple Math
Purplemath: Sectors, Areas, and Arcs
Explains formulas for areas of sectors of circles and lengths of arcs. Demonstrates how to use the formulas in each of degrees and radians.
The Math League
The Math League: Area and Perimeter
This tutorial provides a brief introduction about what area is, then gives the formulas for area of a square, rectangle, parallelogram, trapezoid, triangle, and circle. Examples of each formula are provided.
Illustrative Mathematics
Illustrative Mathematics: 7.g Eight Circles
In this lesson plan, 7th graders use their knowledge of formulas to determine the area and circumference of a circle.
Khan Academy
Khan Academy: Area and Circumference of Circles Challenge
Try these challenge problems involving area and circumference.
Khan Academy
Khan Academy: Circumference of a Circle
Practice finding the circumference of a circle.
Khan Academy
Khan Academy: Circumference of Parts of Circles
Practice finding circumference of parts of circles.
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.
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.
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.
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.
Alabama Learning Exchange
Alex: Arc Lengths and Sector Areas
Learners 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....
Calculator Soup
Calculator Soup: Surface Area Calculator
Online calculator to calculate the surface area of geometric solids including a capsule, cone, frustum, cube, cylinder, hemisphere, pyramid, rectangular prism, sphere, spherical cap, and triangular prism
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.
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.
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.
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.
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
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...
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.
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,...