An interactive applet and associated web page that demonstrate the concept of an arc. The applet shows a circle with part of it highlighted to identify the arc. Each endpoint of the arc can be dragged to resize it. The web page has definitions and links to the properties of an arc. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the area of a circle. A circle is shown with a point on the circumference that can be dragged to resize the circle. As the circle is resized, the radius and the area computation is shown changing in real time. The radius and formula can be hidden for class discussion. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page defining a circle. The applet shows a circle where the user can drag the center and a point on the circle. The radius line supports the definition that all points on the circle are a fixed distance from the center. The web page has the definitions of all the circle-related objects, such as diameter, chord etc, with links for each. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

A circle is a simple closed shape. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius. This article is ...

An interactive applet and associated web page that demonstrate the circumference of a circle. The applet shows a circle with a radius line. The radius endpoints are draggable and the circle is resized accordingly. The formula relating radius to circumference is updated continually as you drag. Introduces the idea of Pi. The formula can be hidden for class discussion and estimation. See also the entries for circumference and diameter. See also entries for radius and diameter. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Through this lesson and its two associated activities, students are introduced to the use of geometry in engineering design, and conclude by making scale models of objects of their choice. The practice of developing scale models is often used in engineering design to analyze the effectiveness of proposed design solutions. In this lesson, students complete fencing (square) and fire pit (circle) word problems on two worksheets—which involves side and radius dimensions, perimeters, circumferences and areas—guiding them to discover the relationships between the side length of a square and its area, and the radius of a circle and its area. They also think of real-world engineering applications of the geometry concepts.

An interactive applet and associated web page that provide step-by-step instructions on how to find the center of a circle using only a compass and straightedge. The method used involves constructing the perpendicular bisectors of two random chords. The bisectors intersect at the center of the circle. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Overall Goal: During this lesson we will cover basic shapes and learn how they can be used in everyday objects. Our goal is for students to know the basic shapes, find them in objects such as playgrounds, be able to create their own playground using shapes, and finally be able to tell the class about the playground they made and the shapes used.  Standard: K.G.3: Model shapes in the world by composing shapes from objects (e.g., sticks and clay balls) and drawing shapes. Learning Objectives: The students will be able to show they know what each of the basics shape are by correctly drawing a square, triangle, rectangle, circle, and oval.Students will be able to create playground with the basic shapes by using everyday objects such as play-doh, craft sticks, etc.Students will be able to complete the project by creating their dream playground; using all of the shapes covered in the lesson.Students can explain their playgrounds and shapes they used, and why their specific playground represents their “dream playground” by presenting their project to the class. Key Terms:SquareRectangleTriangleOvalCircle Lesson Introduction:We will visit the school playground to have the students find the different shapes in the playground equipment. We want students to use the playground visit to help them decide how they would build their dream playground using the basic shapes. We will give the students a packet (found in the Resources section) that includes a few activities for them to do before the main lesson. They will take this to the playground and fill out the second page by writing down the different playground structures that fit each shape. They will be able to explore the playground on their own, so that they can have different answers than each other. Main Lesson:In class, we will have the students create, by drawing, their ‘dream playground’ using the specific basic shapes they are given to work with (squares, triangles, circles, rectangles, and ovals). They will be given 20 minutes to complete their drawing. They will be able to draw this on paper or use a computer application to create this.After this, the students will be given play-doh and popsicle sticks to recreate the shapes and structures that they had on their paper. The crafting process should take around 50 minutes. The drawings and crafts will be assessed by if the students correctly demonstrate their knowledge of the different shapes and how to create them.At the end, the kids will present their own playgrounds to the class and show what shapes they used and be able to explain and defend why it is their dream playground. This is so that the teacher can tell if the student knows the shapes and is able to defend their argument of what makes it a dream playground. The students will be able to use pencil and paper to draw or use tablets/iPads and use a drawing application. Lesson Ending:When the students are done creating their projects, they will each present their playgrounds to the class and explain the individual shapes that they used. The students will also explain why they believe their playground model is the best. The students should answer the following questions when they defend why their playground is the best. How many of each shape are in your playground? Is one of the five shapes better for making playgrounds than the others and why? The way that we can assess is if the student created the shapes correctly and correctly referenced them in their presentation. Rubric:The students will be graded as Good, Average, or Poor. The following is what they are going to be graded on:Students know basic shapesStudents use shapes correctly to build a playgroundStudents complete all parts of the projectStudents present their playgrounds to the class and can explain how they built their playground with the basic shapes Differentiation:This project should not affect students of different gender, race, culture, or sexual identity. Students with behavioral challenges will be worked more one-on-one than the other students to make sure that any confusion or frustration will be handled. The higher ability learners can go beyond the four shapes specified, if they feel comfortable. The project does not require out of school time where they would absolutely need a computer or Wifi access.Examples:If high ability students feel like they can add shapes that are not on the required list, they may do so with permission from the teacher. They will not be given any extra credit for adding other shapes, but this is a good way for the teachers to see where some students are at academically.If there is a child with dyslexia they will receive extra help from the teacher to be sure that they can accurately read the instructions on the papers.If a student needs to use a computer drawing application for sketching the playground because of a disability but doesn’t understand how to use it, they may come into class early to spend some extra time navigating the site.Since the students will be doing a worksheet after the activity, there might be students who struggle with reading. If the students struggle with reading the worksheet, they may ask, and we will help them through the parts that they find confusing. If the student has translation issues with some of the words, we will also help them translate it. This will be done just through being familiar with the material and specific language. Anticipated Difficulties:There could be difficulty with children being distracted at the playground and while crafting. We will need to be sure that everyone is staying on task by keeping them engaged during all of the activities. Children can sometimes become distracted if they are just listening to someone speak and by keeping them engaged and involving them during all of the lesson they will be more likely to stay focused. When on the playground we can use students to help point out the shapes that we find and also ask questions during this time to keep students attentive. Students might be at different learning levels and could struggle with learning the shapes. If so, we could always split the children into a few groups based on learning levels to help the lesson run smoother.

An interactive applet and associated web page that demonstrate the inscribed angle of a circle - the angle subtended at the periphery by two points on the circle. The applet presents a circle with three points on it that can be dragged. The inscribed angle is shown and demonstrates that it is constant as the vertex is dragged. Links to other related topics such as Thales Theorem. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Working as a team, students discover that the value of pi (3.1415926...) is a constant and applies to all different sized circles. The team builds a basic robot and programs it to travel in a circular motion. A marker attached to the robot chassis draws a circle on the ground as the robot travels the programmed circular path. Students measure the circle's circumference and diameter and calculate pi by dividing the circumference by the diameter. They discover the pi and circumference relationship; the circumference of a circle divided by the diameter is the value of pi.

The lesson refers to: The circle, its circumference, its areaPi and Fi numberPolygons and the sum of their interior and exterior anglesThe Golden RatioFibonacci’s Sequence and Spiral                                  

During the warm-up students will review how to sign shapes and the cardinal numbers from the slideshow. For the main activity, students will pair up and each grab a picture card without showing it to their partner. One student will describe the picture card being specific to location, color, etc, while the other draws what their partner just described to them. The partners will then switch roles.

Students learn that math is important in navigation and engineering. They learn about triangles and how they can help determine distances. Ancient land and sea navigators started with the most basic of navigation equations (speed x time = distance). Today, navigational satellites use equations that take into account the relative effects of space and time. However, even these high-tech wonders cannot be built without pure and simple math concepts — basic geometry and trigonometry — that have been used for thousands of years.

This video is meant to be a fun, hands-on session that gets students to think hard about how machines work. It teaches them the connection between the geometry that they study and the kinematics that engineers use -- explaining that kinematics is simply geometry in motion. In this lesson, geometry will be used in a way that students are not used to. Materials necessary for the hands-on activities include two options: pegboard, nails/screws and a small saw; or colored construction paper, thumbtacks and scissors. Some in-class activities for the breaks between the video segments include: exploring the role of geometry in a slider-crank mechanism; determining at which point to locate a joint or bearing in a mechanism; recognizing useful mechanisms in the students' communities that employ the same guided motion they have been studying.

In this Cyberchase video segment, Harry tries to snowboard and learns how to measure and identify many common angles.