As written, this problem gives students all of the information they need to estimate the thickness of a soda can.

his is a version of ''How thick is a soda can I'' which allows students to work independently and think about how they can determine how thick a soda can is. The teacher should explain clearly that the goal of this task is to come up with an ''indirect'' means of assessing how thick the can is, that is directly measuring its thickness is not allowed.

The purpose of this task is to gain experience showing how angle relationships and the properties of triangles can be used to find unknown angles. The students work through various ways to find the missing angles using an understanding of the additive nature of angles. In addition to the examples provided they have additional worksheets available for practice or enrichment.

This rich task is an excellent example of geometric concepts in a modeling situation and is accessible to all students. In this task, students will provide a sketch of a paper ice cream cone wrapper, use the sketch to develop a formula for the surface area of the wrapper, and estimate the maximum number of wrappers that could be cut from a rectangular piece of paper.

This lesson unit is intended to help you assess how students reason about geometry and, in particular, how well they are able to: use facts about the angle sum and exterior angles of triangles to calculate missing angles; apply angle theorems to parallel lines cut by a transversal; interpret geometrical diagrams using mathematical properties to identify similarity of triangles.

This is a Professional Development Resource to support the implementation of a high-quality math resource (Math Expressions, 2018), and provide professional learning around the Geometry progressions.  This professional learning is appropriate for all levels of math educators but focuses on math education for grades 5-8.  It provides educators an opportunity to develop a deeper understanding and make connections to their own grade level Geometry standards. 

Professional Development Resource to support the implementation of a high-quality math resource (Math Expressions, 2018), and provide professional learning around the Geometry Progressions.  This professional learning is appropriate for all levels of math educators but focuses on math education for grades 5-8.  It provides educators an opportunity to develop a deeper understanding and make connections to their own grade level Geometry standards. 

Thsi is a Professional Development Resource to support the implementation of a high-quality math resource (Math Expressions, 2018), and provide professional learning around the Geometry Progressions.  This professional learning is appropriate for all levels of math educators but focuses on math education for grades 5-8.  It provides educators an opportunity to develop a deeper understanding and make connections to their own grade level Geometry standards. 

Professional Development Resource to support the implementation of a high-quality math resource (Math Expressions, 2018), and provide professional learning around the Geometry Progressions.  This professional learning is appropriate for all levels of math educators but focuses on math education for grades 5-8.  It provides educators an opportunity to develop a deeper understanding and make connections to their own grade level Geometry standards. 

This is a pre and post survey given to staff as a part of the professional development provided to math educators in the area of Geometry.  

This task shows how to inscribe a circle in a triangle using angle bisectors. A companion task, ``Inscribing a circle in a triangle II'' stresses the auxiliary remarkable fact that comes out of this task, namely that the three angle bisectors of triangle ABC all meet in the point O.

This task is primarily for instructive purposes but can be used for assessment as well. Parts (a) and (b) are good applications of geometric constructions using a compass and could be used for assessment purposes but the process is a bit long since there are six triangles which need to be constructed.

This task provides an opportunity for students to apply triangle congruence theorems in an explicit, interesting context.

This problem introduces the circumcenter of a triangle and shows how it can be used to inscribe the triangle in a circle. It also shows that there cannot be more than one circumcenter.

This task focuses on a remarkable fact which comes out of the construction of the inscribed circle in a triangle: the angle bisectors of the three angles of triangle ABC all meet in a point.

This lesson unit is intended to help teachers assess how well students are able to use geometric properties to solve problems. In particular, it will help you identify and help students who have difficulty: decomposing complex shapes into simpler ones in order to solve a problem; bringing together several geometric concepts to solve a problem; and finding the relationship between radii of inscribed and circumscribed circles of right triangles.

The applets in this Interactive Geometry Dictionary (IGD) will allow students an opportunity to explore finding the area of some common shapes. The applets demonstrate how to find the area of a triangle using the area of a parallelogram, which in turn can be found using the area of a rectangle. This tool also supports the lesson "What's My Area" cataloged separately.

In this lesson students are introduced to various types of symmetry. After exploring the symmetries that exist with letters of the alphabet, they make inversions of their own name. Suggestions for implementation and support materials are provided.

This Java interactive tool can be used to create dynamic drawings on an isometric dot grid, and to explore volume, surface area, and congruence concepts. Users can draw figures using edges, faces, or cubes and can shift, rotate, color, decompose, and view figures in 2‑D or 3‑D with this applet. Instructions on using and exploring with the tool are included on the page. A related multi-lesson unit from Illuminations for middle school students is linked to the side.

This task is closely related to very important material about similarity and ratios in geometry.