Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Angle Bisection and Midpoints of Line Segments

For Teachers 9th - 10th Standards
This task provides a construction of the angle bisector of an angle by reducing it to the bisection of an angle to finding the midpoint of a line segment. Aligns with G-CO.D.12.
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 5.1 Copies of Line Segments and Angles

For Students 9th - 10th Standards
Construct a copy of a line segment in this interactive exercise.
Interactive
Mocomi & Anibrain Digital Technologies

Mocomi: Lines and Angles

For Students 2nd - 8th Standards
Provides details about the properties of straight lines, types of straight lines, line segments, rays, curved lines, and types of angles.
Lesson Plan
Homeschool Math

Homeschool Math: Lines, Rays, and Angles

For Teachers 4th - 5th Standards
This fourth-grade geometry lesson teaches the definitions for a line, ray, angle, acute angle, right angle, and obtuse angle. We also study how the size of the angle is ONLY determined by how much it has "opened" as compared to the whole...
Activity
Other

Advogato: Trigonometry by Geometric Construction

For Students 9th - 10th Standards
This site from Advogato is all about angles. It contains information starting with what an angle is and what it looks like, all the way up to bisecting angles and theorems about angles. This is very good information for students just...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe, F Tf Coordinates of Points on a Circle

For Teachers 9th - 10th Standards
For this task, students are shown a unit circle in a plane and an angle measured from the x-axis. They must determine the coordinates of the line segment for the angle and answer a question about the sum of the coordinates. The purpose...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: Reflections, Rotations, and Translations

For Teachers 8th Standards
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...
Handout
Purple Math

Purplemath: Conventions

For Students 9th - 10th Standards
A "convention" is "just the way a thing is done!". This reference material lists some common conventions (notational assumptions) for geometry and trigonometry.