Circles aren't functions, so how is it possible to write the equation for a circle? Pupils first develop the equation of a circle through application of the Pythagorean Theorem. The lesson then provides an exercise set for learners to...

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...

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...

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...

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...

Anyone can draw a square, but can you CONSTRUCT a square? Here is a resource that challenges math scholars to create steps to finish their own construction. They test their ability to read and follow directions to complete a construction...

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.

There are an infinite number of points on a circle; can you find nine of them? After putting together a nine-point circle, pupils use constructions and their knowledge of triangle segments to determine the center of the circle. Learners...

Eighth graders classify geometric figures.  In this polygon lesson, 8th graders identify given geometric figures.  They compare and contrast different polygons.  Students name line segments, identify parallel lines, and...

Solids come in many shapes and sizes. Using geometry, scholars create two-dimensional cross-sections of various three-dimensional objects. They develop the lesson further by finding the volume of solids. The module then shifts...

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.

Students identify lines, and line segments. In this geometry lesson plan, students divide line segments into equal congruent parts. They complete a laboratory activity dealing with lines and segments.

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

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...

Students discover the value of Pi.  In this value of Pi lesson, students measure the circumference and diameter of various circles on their graphing calculator.  Students find the ratio of the circumference to the diameter and...

Students use the secant and secant segment theorem to solve problems. In this calculus lesson, students identify where the secant line crosses on a circle. They create circles and secants using cabri software.

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.

Learners 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 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.

Students make conjectures of intersecting circles. In this geometry lesson, students observe circles and their position in space. They investigate and observe two and three dimensional objects.

Students identify properties of circles. In this geometry instructional activity, students identify the center of two intersecting circles.They use Cabri software to create circles and move it around to make observation.

Learners construct tangent lines. In this geometry instructional activity, students identify the point of tangency, secant and tangent lines. They graph the lines on the Ti and make observations.

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.