CK-12 Foundation
Ck 12: Geometry: Perpendicular Lines
[Free Registration/Login may be required to access all resource tools.] Use perpendicular line properties and theorems.
Khan Academy
Khan Academy: Equation Practice With Vertical Angles
Given algebraic expressions that represent a pair of two vertical angles, form and solve an equation. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
CK-12 Foundation
Ck 12: Elem Math: Visually Evaluating Parallel Lines Cut by a Traversal
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems about parallel lines cut by a transversal.
CK-12 Foundation
Ck 12: Geometry: Properties of a Circle Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide reviews the terminology for circles (tangent, arcs, central angles) and the equation for a circle.
Illustrative Mathematics
Illustrative Mathematics: Reflections, Rotations, and Translations
This task uses GeoGebra software, which can be freely downloaded, to explore what happens to the line segments and angles of a triangle when it is reflected, rotated, and translated. Includes printable task sheet for students and a...
Math Is Fun
Math Is Fun: Parallel Lines
Students learn about parallel lines and pairs of angles. Definitions and examples are included.
Texas Instruments
Texas Instruments: Cabri Geometry Tour
In this activity, students use the Cabri software to mark points, draw lines, construct parallel and perpendicular lines, angles, bisectors, and triangles. They learn how to use the tool to measure angles.
Other
Desmos: Geometry Scavenger Hunt
Use the Desmos transformation tools (link at top of page) to complete this scavenger hunt. There are three levels to choose from and solutions are included.
The Math League
The Math League: Figures and Polygons
This site provides definitions of different types of polygons and figures.
Khan Academy
Khan Academy: Finding Angle Measures Between Intersecting Lines
Use your knowledge about angles to find missing angle measures in various situations. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Math Planet
Math Planet: Geometry: Measure Line Segments
Explores how to measure the length of a line segment through examples and a video lesson. [0:40]
Math Planet
Math Planet: Geometry: Polygons
A definition, examples, and a video lesson all help to explain polygons. [0:43]
Math Planet
Math Planet: Geometry: Finding Distances and Midpoints
Discover how to find distances and midpoints by viewing examples and a video lesson. [1:07]
CK-12 Foundation
Ck 12: Geometry: Angles Outside a Circle Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to calculate angles formed outside a circle by tangent and secant lines.
CK-12 Foundation
Ck 12: Geometry: Angles on and Inside a Circle Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to find angles on and inside a circle created by chords and tangent lines.
Oswego City School District
Regents Exam Prep Center: Bisect a Line Segment and an Angle
This step-by-step tutorial teaches students how to construct a bisector of a segment and the bisector of an angle.
CK-12 Foundation
Ck 12: Angle Bisectors in Triangles
[Free Registration/Login Required] Students will use interactive triangles to explore how a line bisects an angle. Click learn more to watch a video and click challenge me to answer a practice question.
CK-12 Foundation
Ck 12: Angles Outside a Circle
[Free Registration/Login Required] Students will move the points on the line segments to explore anlge measures outside the circle. Click learn more to watch a video and click challenge me to answer a practice question.
Oswego City School District
Regents Exam Prep Center: Geometric Constructions
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...
ClassFlow
Class Flow: Plane Geometry
[Free Registration/Login Required] This is an introduction or review lesson on points, lines, planes and angles using some of the tools for Activstudio 2.
Other
Antonio Gutierrez: Geometry From the Land of the Incas
Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...
Illustrative Mathematics
Illustrative Mathematics: G Gpe Slopes and Circles
The purpose of this task is to lead young scholars through an algebraic approach to a well-known result from classical geometry, namely, that a point X is on the circle of diameter AB whenever angle AXB is a right angle. This consists of...
ClassFlow
Class Flow: Angles in Geometry
[Free Registration/Login Required] This flipchart is a look at angles in geometry. Drawing, labeling, measuring, special angles: (right, straight, acute, obtuse) and congruence.
Texas Instruments
Texas Instruments: Parallel Lines
This file contains questions related to parallel lines cut by a transversal and the angles formed. The questions can be used to asses your students' understanding of this topic in geometry.