So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be 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...

Students explore uniform circular motion, and the relation of its frequency of N revolutions/sec with the peripheral velocity v and with the rotation period T, and the "centripetal acceleration" of an object.

You know the Inscribed Angle Theorem and you know about tangent lines; now let's consider them together! Learners first explore angle measures when one of the rays of the angle is a tangent to a circle. They then apply their...

High schoolers play the "space-breaker" game, in which they are required to create a picture using shapes or lines called out to them) to reinforce the concept of geometric shape and line.

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...

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

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...

Students investigate proofs used to solve geometric problems. In this geometry activity, students read about the history behind early geometry and learn how to write proofs correctly using two columns. The define terminology valuable to...

You've investigated relationships between chords, radii, and diameters—now it's time for arcs. Learners investigate relationships between arcs and chords. Learners then prove that congruent chords have congruent arcs, congruent arcs have...

Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...

Ninth graders, after being given a unique scenario and a task sheet on Dead Man's Curve, calculate and explain the force needed to keep a car on a curve using a set of formulas and a geometric property of circles. They utilize and create...

Learners study about deriving centripetal acceleration for motion at constant speed around a circle.

Students explore uniform circular motion, and the relation of its frequency of N revolutions/sec with the peripheral velocity v and with the rotation period T. They examine how uniform circular motion is a type of accelerated motion.

Students create a picture of an actual scene or overlap the called out lines or shapes into a space-breaker. If someone calls out a line or shape a student had not planned to use in the art, they have to figure out some way to use it...

Students analyze a drawing of a regular octagon inscribed in a circle to determine angle measures, using knowledge of properties of regular polygons and the sums of angles in various polygons to help solve the problem. They use...

Students explore the concept of vertex-edge graphs.  In this vertex-edge graphs lesson plan, students try to construct a graph with a given diameter, number of vertices, size, and planarity.  Students construct various...

Students, as a final project, draw a picture of their ideal neighborhood on a sunny day. In addition to the sun, their drawings include homes, trees, streets, and selected objects. Each object in their drawing has a written description...

How do you prepare class members for the analytical thinking they will need in the real world? An assessment requires the higher order thinking they need to be successful. The module focuses on the concept of rigid transformations...

Triangle centers and the segments that create them easily become an exercise in memorization, without the help of engaging applications like this lesson. Here the class investigates the measure of center that is equidistant to the three...

Fifth graders devise and use problem solving strategies to solve a magic square arrangement. In small groups they explore various strategies including non-algebraic and algebraic techniques, write an explanation of their solution, and...

Students examine a math worksheet and determine how to divide a single triangle into four of equal area. Using geometric principles, they sketch two additional ways to divide into into four equal triangles. To conclude, students...

Here is a project that combines Computer Science and Mathematics. The semicircle has two tangent lines that meet at point T. You need to prove that a line drawn from A to T bisects CD. You'll also learn how to create an interactive...