After reviewing types of angles and how to measure angles using a protractor, students will see how many triangles they can construct using an 18-foot beam.  Through this activity, students will discover the conditions that must be met to construct a triangle.  For example, the sum of the lengths of two sides of a triangle must be greater than the longest side of the triangle.  They will also discover that the sum of the angles of a triangle is always 180 degrees.

This lesson unit is intended to help teachers assess how well students are able to: work with concepts of congruency and similarity, including identifying corresponding sides and corresponding angles within and between triangles; Identify and understand the significance of a counter-example; Prove, and evaluate proofs in a geometric context.

The purpose of this task is to help students understand what is meant by a base and its corresponding height in a triangle and to be able to correctly identify all three base-height pairs.

This book is a "flexed" version of CK-12's Basic Geometry that aligns with College Access Geometry and contains embedded literacy supports. It covers the essentials of geometry for the high school student.

CK-12 Foundation's Geometry FlexBook is a clear presentation of the essentials of geometry for the high school student. Topics include: Proof, Congruent Triangles, Quadrilaterals, Similarity, Perimeter & Area, Volume, and Transformations.

This animation demonstrates how to construct triangles if you know the lengths of a triangle's 3 sides using a ruler and drafting compass.

A structured geometry program teacher edition of daily lesson plans and teacher supports to accompany the College Access Reader: Geometry student edition.

CK-12 Foundation's Geometry FlexBook is a clear presentation of the essentials of geometry for the high school student. Topics include: Proof, Congruent Triangles, Quadrilaterals, Similarity, Perimeter & Area, Volume, and Transformations.

This lesson unit is intended to help teachers assess how well students are able to use geometric properties to solve problems. In particular, the lesson will help you identify and help students who have the following difficulties: solving problems by determining the lengths of the sides in right triangles; and finding the measurements of shapes by decomposing complex shapes into simpler ones. The lesson unit will also help students to recognize that there may be different approaches to geometrical problems, and to understand the relative strengths and weaknesses of those approaches.

CK-12's Texas Instruments Geometry Student Edition Flexbook is a useful collection of exercises intended to enrich a student's understanding of basic geometric principles.

CK-12's Texas Instruments Geometry Teacher's Edition Flexbook is a useful collection of exercises intended to enrich a student's understanding of basic geometric principles.

CK-12 Geometry Teacher's Edition covers tips, common errors, enrichment, differentiated instruction and problem solving for teaching CK-12 Geometry Student Edition. The solution and assessment guides are available upon request.

This document is from NC2ML and state leaders. It provides an overview for teachers about the mathematics and pedagogies in Grade 3 Cluster 5. This is not remixable since it is from state leaders.

In this lesson, students learn the attributes of triangles by constructing them from various side lengths.

In this lesson, students explore various triangles by sorting them based on attributes such as having equal lengths and square corners (right angles).

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.

The purpose of this lesson is to help students investigate the relationships of the lengths of the sides of a triangle in order to discover the three triangle inequality theorems. Students will learn how to draw valid conclusions from the information obtained from the activity and apply those conclusions to real world geometry problems. This serves as an introduction into more advanced geometric theorems.

This task is intended for instruction, providing the students with a chance to experiment with physical models of triangles, gaining spatial intuition by executing reflections.

In this assessment task students use pattern blocks to make the hexagons outlined on workmats. They are asked to make the shape in different ways. Teachers can observe students using slides, flips and turns as they make the shapes. The assessment workmat and a rubric are provided.