Worksheet
Curated OER

Regents Exam Questions G.G.21: Centroid, Orthocenter, Incenter, and Circumcenter

For Students 9th - 12th
In this triangles worksheet, high schoolers solve 4 multiple choice problems. Students find the centroid, orthocenter, incenter, and circumcenter or various triangles.
Worksheet
Curated OER

Constructions and Loci

For Students 9th - 10th
In this geometry worksheet, students construct polygons and calculate the different angles formed by each shape. They construct circles, trapezoids, and rectangles and answer 20 questions.
Worksheet
Curated OER

Concurrent Lines, Medians and Altitudes

For Students 9th - 10th
For this geometry worksheet, students construct angles and identify medians and altitudes. They use a compass and protractor to perform heir construction. There are 28 questions.
Lesson Plan
Curated OER

The Search for Pythagoras' Treasure

For Teachers 8th - 10th
Students identify and define properties of triangles. In this geometry lesson plan, students identify the missing sides and angles of right triangles. They use the rules of the Pythagorean Theorem to solve their problems.
Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
Students solve problems using geometric means. In this geometry instructional activity, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
Student identify the solution using geometric mean. In this geometry lesson, students create right triangles where the altitude of the triangle is the side containing the right angle. They modify shapes using Cabri software and observe...
Handout
Lockport City School District

Reasons for Geometric Statement/Reason Proofs

For Students 8th - 11th Standards
Stuck trying to remember the formal language of a geometric proof? Never fear, this handout has them all ready to go. The reasons are sectioned by topic so this handy guide is ready when you are to tackle those two column proofs. 
Unit Plan
Mathematics Vision Project

Module 6: Congruence, Construction, and Proof

For Teachers 8th - 10th Standards
Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...
App
Bytes Arithmetic

Geometry Pad+

For Students 6th - 10th Standards
Graphing paper, pencil, ruler, protractor, and compass, all get replaced or supplemented with this dynamic geometry application. Here, you can create, move, and scale many different shapes, as well as, explore and change their properties...
Worksheet
Curated OER

Lesson 5.3 Vocabulary Quiz: Concurrent Lines, Medians, & Altitudes

For Students 10th - 12th
In this vocabulary activity, students match a given vocabulary word to the correct definition.  Words include such terms as altitude, centroid, circumcenter, circumscribed circle, inscribed circle, median and orthocenter. ...
Lesson Plan
Curated OER

Making Shapes

For Teachers 10th
Tenth graders construct geometric figures using compasses and protractors.
Unit Plan
Cuemath

Cuemath: Angle Bisector Theorem

For Students 9th - 10th Standards
This short lesson focuses more on the angle bisector theorem. Learn about the angle bisector theorem proof, triangle angle bisector theorem, how to construct angle bisector, and other interesting properties and facts around angle bisectors.
Unknown Type
Khan Academy

Khan Academy: Solve Triangles: Angle Bisector Theorem

For Students 9th - 10th Standards
Use the Angle Bisector Theorem to find missing side lengths in triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Unknown Type
Khan Academy

Khan Academy: Solve Triangles: Angle Bisector Theorem

For Students 9th - 10th Standards
Use the angle bisector theorem to find missing side lengths in triangles.
Handout
Wolfram Research

Wolfram Math World: Angle Bisector

For Students 9th - 10th
MathWorld offers a definition for an interior angle bisector accompanied by an example this site also gives a formula for the lenght of the bisector of a triangle.
Activity
Texas Instruments

Texas Instruments: Altitude, Median, and Angle Bisector of a Triangle

For Teachers 9th - 10th
In this activity, you will construct special segments of a triangle named altitudes, medians, and angle bisectors, Using their definitions. You will look at how an altitude, a median, and an angle bisector divide the area of a triangle....
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Angle Bisectors in Triangles

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] Apply angle bisector properties.
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Angle Bisectors in Triangles Intermediate

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] This concept teaches students properties of angle bisectors and how to apply them.
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Proportions With Angle Bisectors

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] Apply the fact that an angle bisector divides a triangle proportionally.
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Proportions With Angle Bisectors

For Students 9th - 10th
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to set up and solve proportions with angle bisectors.
Handout
CK-12 Foundation

Ck 12: Geometry: Bisectors, Medians, Altitudes Study Guide

For Students 9th - 10th
This study guide on bisectors, medians, and altitudes covers key vocabulary, different theorems, and facts about the altitude and triangles. It is available for download with free registration.
Activity
Texas Instruments

Texas Instruments: Incenter of a Triangle

For Teachers 9th - 10th
In this activity, students observe a special characteristic of the bisectors of the angles in a triangle. They test their conjecture by changing the size and shape of the triangle.
Interactive
CK-12 Foundation

Ck 12: Angle Bisectors in Triangles

For Students 9th - 10th Standards
[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.
Activity
Texas Instruments

Texas Instruments: Triangle Properties Assessment

For Teachers 9th - 10th
This activity uses Cabri Jr. to assess the students' knowledge of various segments related to triangles: perpendicular bisector, median, angle bisector, midsegment, and altitude.