Futures Channel
Folding Circles
Students investigate properties of circles. In this geometry lesson, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
EngageNY
Circles, Chords, Diameters, and Their Relationships
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...
Curated OER
Altitudes and Orthocenters: Making Connections to the Nine-Point Circle
Students practice various equations for constructing nine-point circles for triangles.
EngageNY
How Do Dilations Map Lines, Rays, and Circles?
Applying a learned technique to a new type of problem is an important skill in mathematics. The lesson asks scholars to apply their understanding to analyze dilations of different figures. They make conjectures and conclusions to...
Curated OER
Circle Conjectures
Students are given diagrams and are asked to make a conjecture. In this geometry instructional activity, students make conjectures of circles. They complete a lab activity to reinforce making conjectures. The first activity addresses a...
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.
Curated OER
Exploring Harmonic Conjugates
High schoolers investigate harmonic conjugates using Cabri Software or the Ti Calculator to analyze harmonics. They explore different angles measurements as they move their circles around and solve problems.
Curated OER
Connecting Formulas Related to Geometric Figures
Young scholars identify diagrams of quadrilaterals and circles by different names and classify the figures. They name the areas for each diagram and practice solving the formulas for each.
Curated OER
Conjectures of Intersecting Circles
Young scholars make conjectures of intersecting circles. In this geometry activity, students observe circles and their position in space. They investigate and observe two and three dimensional objects.
EngageNY
Tangent Segments
What's so special about tangents? Learners first explore how if a circle is tangent to both rays of an angle, then its center is on the angle bisector. They then complete a set of exercises designed to explore further properties and...
Curated OER
Conjectures For Intersecting Circles
Students identify properties of circles. In this geometry lesson, students identify the center of two intersecting circles.They use Cabri software to create circles and move it around to make observation.
Curated OER
Circle, Secants
Students identify the secant segment of a circle. In this geometry lesson, students investigate secant lines formed outside the circle. They use Cabri software to create drawings and explore circles and secants.
Curated OER
Cabri Jr. Perpendicular Bisector of a Chord
Your learners will construct the perpendicular bisector of a chord. They use Cabri Jr. to construct a circle and a perpendicular bisector of a chord. They then measure lengths of the chords and perpendicular bisectors. Learners use...
Curated OER
Cabri Jr. Inscribed Angles
Young scholars construct inscribed angles using Cabri Jr. They draw a circle on their graphing calculator, then construct an inscribed angle and measure its angle measures. Learners drag the inscribed angle around the circle. They make...
Curated OER
Segments Formed by Intersectiong Chords, Secants, and Tangents
Learners investigate the properties of segments formed which chords, secants, and tangents, intersect. The dynamic nature of Cabri Jr. allows learners to form and verify conjectures regarding segment relationships.
EngageNY
Secant Angle Theorem, Exterior Case
It doesn't matter whether secant lines intersect inside or outside the circle, right? Scholars extend concepts from the previous lesson to investigate angles created by secant lines that intersect at a point exterior to the circle....
Noyce Foundation
Pizza Crusts
Enough stuffed crust to go around. Pupils calculate the area and perimeter of a variety of pizza shapes, including rectangular and circular. Individuals design rectangular pizzas with a given area to maximize the amount of crust and do...
Texas Instraments
Angles in Circles
Teach your learners how to investigate the relationship between a central angle and an inscribed angle which subtend the same arc of a circle. The dynamic nature of Cabri Jr. provides opportunity for conjecture and verification.
Curated OER
Inscribing a Circle in a Triangle
Pupils investigate inscribing a circle in a triangle. They use Cabri Jr. to draw a triangle, locate the incenter, and use the distance from the incenter to a side of the triangle to inscribe a circle. The dynamic nature of the geometry...
Curated OER
Determining the Uniqueness of a Circle
Young scholars use this lesson to determine how circles are different from other shapes. In groups, they determine the accuracy of three theorems based on the uniqueness of circles. They use a software program to hypothesize about the...
Curated OER
Evaluating the Products of Chords of a Circle
Students investigate chords and make predictions. In this geometry lesson, students graph circles and calculate the measurement of each chord. They perform the calculations and make conjectures.
Curated OER
Tangent Properties
Students explore properties of tangent lines. In this properties of tangent lines lesson plan, students discuss the perpendicular relationship between a tangent line on a circle and the circle's radius. Students use that relationship...
Curated OER
Exploring the Witch of Agnesi
high schoolers construct the graph of the Witch of Agnesi, and investigate both its asymptotes and inflection points. They construct the graph of the Witch of Agnesi and conjecture the asymptotes and inflection points of the function. ...
EngageNY
Examples of Dilations
Does it matter how many points to dilate? The resource presents problems of dilating curved figures. Class members find out that not only do they need to dilate several points but the points need to be distributed about the entire curve...