This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons...

Take young mathematicians on an exploration of the world of 3-D geometry with this seven-lesson unit. After first defining the terms perimeter, area, and volume and how they apply to the real world, students continue on...

Have you hit a wall when trying to create performance task questions? Several open-ended response questions require a deep level of thinking. Topics include triangle congruence, quadrilaterals, special segments, constructions, and...

Construct yourself a winning geometry unit. A set of lessons introduces geometry scholars to constructions and proofs with compasses and straightedges. It also covers triangle congruence through transformations. This is the second of...

Scholars construct three-dimensional figures to study dimension and side views. Learners build models using linking cubes to match views of different sides. After practicing with models, they attempt to match three-dimensional drawings...

Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...

Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...

Noah didn't construct this kind of arc. High school scholars first explore how angles can be formed in circles. They then learn relationships between angles and arcs by conducting an exploratory activity where they position and draw arcs...

Need an activity for teaching the Pythagorean Theorem? Geometry juniors apply the Pythagorean theorem to two triangles to determine a final calculation. 

Challenge the spatial thinking of your young mathematicians with this printable tangram puzzle. Using different sized triangles, squares, and parallelograms, children must figure out how to fit all the shapes together to create a square.

Turn young mathematicians into landscape architects with this four-lesson series on area and perimeter. Beginning with a basic introduction to calculating perimeter and area using non-standard units of measurement, this...

Evaluate young mathematicians' understanding of area and perimeter with this series of three assessment tasks. Challenging students to not only calculate the area and perimeter of irregular shapes, but to explain in writing their...

How do you know if a pair of triangles are congruent? Use the lesson to help class members become comfortable identifying the congruence criteria. They begin with an exploration of ASA and SSS criteria through transformations and...

What is the fastest way to get from point A to line l? A straight perpendicular line! Learners use what they have learned in the previous lessons in this series and develop a formula for finding the shortest distance from...

This assessment pair goes way beyond simple graphing, factoring and solving polynomial equations, really forcing learners to investigate the math ideas behind the calculations. Short and to-the-point questions build on one another,...

Most problems can be solved using more than one method. A instructional activity includes just nine questions but many more ways to solve each. Scholars must graph, solve, and justify quadratic problems.

Scholars find a pattern from a geometric sequence and write the formula for extending it. The worksheet includes a table to complete plus four analysis questions. It concludes with instructional implications for the teacher.

Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...

If there is a conditional statement, then there is a hypothesis and conclusion. Pupils learn how to identify the parts of conditional statements. Class members continue to work with conditional statements and rewrite them in their many...

Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....

Learn all about the basic geometric constructions in this test prep lesson. You will explore line segments and points, and understand key terms like the terms parallel and perpendicular. Construction activities and interactive online...

Use Cabri Jr to copy an angle. The activity is followed by a student-to-student interview/reflection sheet intended to require students to think, talk, and write about why the construction worked. The reflection sheet could be adapted...

From the San Francisco 49er's Museum Education Program which promotes STEAM concepts, students construct a three dimensional (3-D) artifact stand that is the exact replica of "The Catch" which is 70 inches high. Emphasis is placed on...

Students use the TI-89 with CABRI Geometry to discover properties of parallelograms. They will construct a figure and use the definition to discover the figure is a parallelogram.