EngageNY
Proving the Area of a Disk
Using a similar process from the first lesson in the series of finding area approximations, a measurement resource develops the proof of the area of a circle. The problem set contains a derivation of the proof of the circumference...
West Contra Costa Unified School District
Finding the Equation of a Circle
Tired of going around and around for a resource on circles? Scholars determine the general equation of a circle on a coordinate plane, then participate in an activity matching equations to the radii and centers of the circles...
Virginia Department of Education
Arc Length and Area of a Sector
What do skateboarding and baked goods have in common with math? You can use them to connect half-pipe ramps and cakes to arcs and sectors. Pupils compare the lengths of three different ramp options of a skate park. They calculate the...
Curated OER
Area of Circles and Probability
Learners investigate the area of squares and circles. In this geometry lesson plan, students calculate the area and probability of simple events. They work on a laptop using Safari.
Willow Tree
Area of Common Geometric Figures
Scholars can use area formulas, but can they apply what they know about area? The lesson challenges learners to think logically while practicing finding area of shapes such as rectangles, circles, parallelograms, triangles, and other...
EngageNY
What Is Area?
What if I can no longer justify area by counting squares? Lead a class discussion to find the area of a rectangular region with irrational side lengths. The class continues on with the idea of lower approximations and...
Texas Instruments
Area of Circles
Students 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.
EngageNY
Area Problems with Circular Regions
Uncover strategies for finding areas of composite figures. The 23rd lesson in a 29-part module has young mathematicians decompose figures to find total area. Figures decompose to rectangles and circular regions.
Curated OER
Chords of a Circle
Teach how to differentiate between chords and perpendicular bisectors. In this geometry lesson, students relate the properties of chords and circle to solving right triangle. They define what makes two chords congruent in side a circle.
Texas Instruments
Drawing a Line Tangent to a Circle
Explore lines tangent to a circle. In this math lesson plan, 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...
Teach Engineering
Discovering Relationships Between Side Length and Area
Consider the relationship between side length and area as an input-output function. Scholars create input-output tables for the area of squares to determine an equation in the first installment of a three-part unit. Ditto for the area of...
Illustrative Mathematics
Stained Glass
A complex question looking for the total cost of a stained glass window by calculating area and circumference of a circle. With detailed components, this activity will challenge your designers to figure out if they have enough money to...
Curated OER
Equation of a Circle
Learners write the equation of a circle. In this geometry lesson, students check the solution of a coordinate pair by evaluating them. They graph the circle given the equation and radius.
EngageNY
Unknown Length and Area Problems
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.
Curated OER
Equations of Circles
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.
Mathematics Assessment Project
Solving Problems with Circles and Triangles
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.
Curated OER
Surface Area, Who Needs it?
In this geometry lesson 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.
Texas Instruments
Areas of Regular Polygons and Circles
Learners explore area of polygons and regular polygons in this math instructional activity. They calculate the area of several polygons using Cabri Jr. and analyze shapes and write formulas to solve for the area.
EngageNY
Arc Length and Areas of Sectors
How do you find arc lengths and areas of sectors of circles? Young mathematicians investigate the relationship between the radius, central angle, and length of intercepted arc. They then learn how to determine the area of sectors of...
Willow Tree
Perimeter of Common Geometric Figures
Help learners understand that perimeter and circumference are one in the same. Learners apply their skills to determine the perimeter/circumference of triangles, rectangles, and circles. They then use the same strategy to find the...
EngageNY
Unknown Area Problems on the Coordinate Plane
Scholars determine distances on the coordinate plane to find areas. The instructional activity begins with a proof of the formula for the area of a parallelogram using the coordinate plane. Pupils use the coordinate plane to determine...
Curated OER
Area and Perimeter
Learners find the area and perimeter of regular polygons and composite figures and examine the effect on the area and perimeter of a figure if the dimensions are multiplied by a constant. The nine page worksheet contains thirty-seven...
Curated OER
The Geometry of Circles
Learners review the parts of a circle, calculate the circumference and area of a circle, and create student-made tests on the geometry of circles using educational software.
EngageNY
Properties of Area
What properties does area possess? Solidify the area properties that pupils learned in previous years. Groups investigate the five properties using four problems, which then provide the basis for a class discussion.