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...

We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson then...

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...

Don't go off on a tangent while writing equations of tangent lines! Scholars determine the equations for tangent lines to circles. They attempt both concrete and abstract examples, such as a tangent line to the unit circle through...

Putting a rectangular object into a circular one—didn't the astronauts on Apollo 13 have to do something like this? Learners first construct the center of a circle using perpendiculars. They then discover how to inscribe a rectangle in a...

High schoolers explore the concept of circles as they construct a circle using a program such as Cabri Jr. Learners construct a chord and a diameter that are perpendicular, then measure the bisected chord and notice that both sides of...

Learners investigate the properties of segments formed which chords, secants, and tangents, intersect. The dynamic nature of Cabri Jr. allows students to form and verify conjectures regarding segment relationships.

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.

Students identify tangents, chords and secants. In this geometry lesson, students graph circles and identify angles created by secant lines, tangent lines and chords.

Students creating chords intersection using circles. In this geometry lesson, students create visuals of chords ad their properties using Cabri technology. They measure the chords and explore the relationship among chords.

Students identify the properties of chords. In this geometry lesson, students multiply chord segments to find the solution to their problem. They construct two chords that cross on  a circles.

High schoolers identify chords and angles. In this geometry lesson, students calculate the length of the chords inside and outside of-the circle. They differentiate between tangent and secant lines.

Pupils 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.

Students are given diagrams and are asked to make a conjecture. In this geometry lesson, students make conjectures of circles. They complete a lab activity to reinforce making conjectures. The first activity addresses a common core...

Learners 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.

Tenth graders explore and define the radius and diameter of a circle. In this geometry activity, 10th graders calculate the circumference and area of a circle using real world objects and shapes. They discuss chords and lines...

Students identify the relationship between chords, secants and circles. In this geometry lesson, students calculate the length of the chords. They sketch the secant lines on a circle.

Students identify different parts and properties of circles. In this geometry lesson, students identify the radius, diameter, semicircle and inscribed angle of a circle. They identify the tangent lines to a circle.

Students explore secants and circles. In this geometry activity, students identify the properties of two and three dimensional shapes. They create arguments to prove the theorems are true.

Mathematicians measure intersecting lines-and circles, and create chords. In this geometry lesson, students explore interrior and exterior chords created by tangent and secant lines. These segments can be inside the circleor outside the...

Students investigate circles and its arcs. In this geometry lesson plan, students identify the relationship between an circle and its intercepted arcs. THey identify the central and inscribed angles.

Students relate the ratio of Pi to the diameter of a circle. In this geometry lesson, students investigate the relationship of the chord of the circle the the number Pi. They define ration, chord, circumference and diameter and find...

Students investigate basic geometric concepts. In this geometry lesson, students explore solids through measuring and modeling. This assignment models the importance of understanding concrete objects in geometry.      

Geometry adventurers study circumference of a circle as they listen to Sir Circumference and the Dragon Pi, by Cindy Neuschwander. In groups, they use string to measure the diameter and circumference of circular objects and...