Students investigate the area of squares and circles. In this geometry instructional activity, students calculate the area and probability of simple events. They work on a laptop using Safari.

How do the area and perimeters of circles and squares compare? A clever video illustrates the change in the area of a circle and square while their total perimeter stays the same. The task is for learners to predict the point where the...

This activity is a follow-on activity to inscribing a square in a circle. The overall problem is more complex. It deals with geometric constructions, properties of triangles, and regular hexagons. The final part of the activity...

Young scholars explore circles. In this algebra/geometry lesson, students discover the formula for the area of a circle, as they investigate the ratio of the area of a circle to the radius^2.

Through the use of Internet, video, and hands-on activities, youngsters learn the parts and characteristics of a circle. This fantastic lesson has some excellent website activities included in the plan. Your kids will have a much greater...

Explore lines tangent to a circle. In this math lesson, students manipulate circles and lines on a TI calculator. They draw a circle  and analyze perpendicular lines intersecting the circle in only one place. This activity works...

Not all structures take the shape of a polygon. The 21st lesson in a series of 29 shows young mathematicians they can create polygons out of composite shapes. Once they deconstruct the structures, they find the area of the composite figure.

What is an annulus? Pupils first learn about how to create an annulus, then consider how to find the area of such shapes. They then complete a problem set on arc length and areas of sectors.

Using Cabri Jr. students construct a circle and determine the equation of the circle they drew by finding the center and the radius. Students use the distance formula to derive the equation of their circle.

Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...

Going around in circles trying to find a resource on sectors of circles? Here is an activity where pupils first complete an assessment task to determine the areas and perimeters of sectors of circles. They then participate in an...

After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.

Explore Apple's spaceship office building. Built in the shape of a circle, the office building offers a unique floor plan challenge. Young scholars use the dimensions of the building to estimate the square footage for each employee. 

In this geometry activity on cylinders, geometers explore how to find the smallest surface area for a given volume.  They use their knowledge to relate it to the real world by making a model of a livestock tank.

You've just hit the jackpot of integrating math problems and riddles with this jumbo-sized resource! Written as a newsletter, scroll through 35 pages of puzzles and quality problems to engage and encourage your learners to inquire...

Students explore different size circles to discover the relationship between diameter and circumference. In this circles and Pi instructional activity, students construct simple parachutes using circle patterns of varying sizes. Students...

It's all about the portion size! Given a photo of a pumpkin pie, learners work to determine the number of calories that are missing. Supplemental information provides the angle of the piece that is missing as well as the nutritional...

Pupils circumscribe a circle about a triangle. They construct a triangle using Cabri Jr and then circumscribe it. They then use knowledge of perpendicular bisectors and circumcenters to locate the center of the circle and then...

Learners develop techniques for estimating the area of a circle and use ideas about area and perimeter to solve practical problems. In this area and perimeter lesson, students apply the concepts of perimeter and area to the solution of...

Math whizzes use the area probability applet to manipulate the size of the circle and the rectangle to explore the probability that a point in the rectangle is also in the circle.

Sew up pupil interest with an engaging, hands-on lesson plan. Learners first design a sports bag given constraints on the dimensions of fabric. They then evaluate provided sample responses to identify strengths and weaknesses of included...

Students construct the circumcenter of a triangle. For this constructing the circumcenter of a triangle lesson, students construct a triangle using Cabri Jr. Students draw perpendicular bisectors of the sides of the triangle. Students...

High schoolers investigate properties of the four centers of a triangle and explore a special property of the circumcenter and orthocenter of a triangle. This lesson requires the use of Cabri, Jr.

Student find the area of a sector of a circle. In this geometry lesson, pupils  define the sector of a circle using a sketch. They find and identify examples of sector in the real world.