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Performance
Radford University

Building a Recreation Center

For Teachers 9th - 12th Standards
It's all about location, location, location. Small groups work to find the best spot for a rec center to serve three different communities. Learners construct the inscribed and circumscribed circles of a triangle to find the best place....
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Performance
Radford University

Finding a Location for Your Kitchen Island

For Teachers 9th - 12th Standards
Where is the best place to work? Small groups map out a kitchen on a coordinate plane and find the centers of the work triangle to find the best place to install an island. The teams use algebraic methods to locate the center by finding...
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Assessment
Concord Consortium

Always, Sometimes, Never

For Students 9th - 10th Standards
Do your learners always, sometimes, or never remember the properties of the segments in triangles? Get that number closer to always with a creative lesson analyzing all four segments. Scholars consider a statement about one of the...
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Lesson Plan
EngageNY

Analytic Proofs of Theorems Previously Proved by Synthetic Means

For Students 9th - 12th Standards
Prove theorems through an analysis. Learners find the midpoint of each side of a triangle, draw the medians, and find the centroid. They then examine the location of the centroid on each median discovering there is a 1:2 relationship....
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Unit Plan
Mathematics Vision Project

Geometric Figures

For Teachers 10th - 12th Standards
Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...
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Lesson Plan
Curated OER

Medians and Altitudes of Triangles

For Teachers 10th
In this geometry worksheet, 10th graders determine if a given segment is a median or altitude of a triangle and use then find the indicated missing length or equation of a line.  The two page worksheet contains twenty problems.  Answers...
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Worksheet
Curated OER

Take Home Question

For Students 9th - 12th
In this slope and perpendicular lines activity, students solve 5 short answer problems. Students find an unknown coordinate given two points, a perpendicular line, and a slope. Students find the centroid of a triangle.
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Worksheet
Curated OER

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

For Students 9th - 12th
In this triangles instructional activity, students solve 4 multiple choice problems. Students find the centroid, orthocenter, incenter, and circumcenter or various triangles.
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Lesson Plan
Curated OER

Properties of the Centers of a Triangle

For Teachers 9th - 12th Standards
High schoolers investigate properties of the four centers of a triangle and explore a special property of the circumcenter and orthocenter of a triangle. This lesson requires the use of Cabri, Jr.
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Worksheet
Math eBook

Centroid of Triangles

For Students 9th - 11th
For this centroid of triangles worksheet, students use given information to determine the centroid of a triangle. They identify the point through which all medians of the triangle pass. This five-page worksheet contains approximately 20...
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Lesson Plan
Curated OER

Exploring Centers of a Triangle: Part 2

For Teachers 10th - 12th
Students model and solve a real-world problem by constructing the centroid of a triangle. They explore relationships of the medians of a triangle and investigate how the centroid partitions each of the medians. Students investigate...
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Worksheet
Curated OER

Concurrence

For Students 10th
In this concurrence worksheet, 10th graders solve 10 different problems related to determining various concurrences. First, they determine which type of triangle has two altitudes outside of it. Then, students determine the distance...
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Activity
Varsity Tutors

Varsity Tutors: Hotmath: Practice Problems: Applications of Integrals

For Students 9th - 10th
Hotmath provides 24 practice problems dealing with integral applications. Each of the practice problems include a step-by-step guide for solving their application.
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eBook
Mathigon

Mathigon: Geometry: Triangles and Trigonometry: Properties of Triangles

For Students 9th - 10th Standards
This lesson focuses on the properties of triangles, a closed shape that has three sides, three vertices, and and three internal angles. There are different types of triangles such as a right triangle, obtuse, and acute based on the...
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Unit Plan
Cuemath

Cuemath: Point of Concurrency

For Students 9th - 10th
Learn all about the point of concurrency. This lesson targets the point of concurrency of perpendicular bisectors, the point of concurrency of the angle bisectors of a triangle, and has interesting solved examples and practice questions.
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Handout
Wolfram Research

Wolfram Math World: Triangle Centroid

For Students 9th - 10th
This site from MathWorld gives a diagram of a triangle with its centroid labeled. The site details how to find the centroid with links to the key terms. The site details many other interesting properties of the triangle centroid.
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Activity
Texas Instruments

Texas Instruments: Numb3 Rs: Irregular Polygon Centroids

For Teachers 9th - 10th
Based off of the hit television show NUMB3RS, this lesson has students explore finding the centroid of an irregular polygon by finding the mean of the coordinates of the polygon's vertices. Further, students find the centroid given that...
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Activity
Texas Instruments

Texas Instruments: Numb3 Rs: Regular Polygon Centroids

For Teachers 9th - 10th
Based off of the hit television show NUMB3RS, this lesson shows students different ways to find centroids of regular polygons. The traditional way (using medians) is presented, as well as the triangulation method, the diagonals method,...
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Activity
Texas Instruments

Texas Instruments: Centers of a Triangle

For Teachers 9th - 10th
The centroid, circumcenter, orthocenter, and incenter are the four classic centers of a triangle that are studied in geometry. In this activity, you will construct these center points and discover their properties. [Requires Adobe Reader.]
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Activity
Texas Instruments

Texas Instruments: Centroid and Orthocenter

For Teachers 9th - 10th
In this activity, students analyze the location of the centroid and orthocenter for different triangles.
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Lesson Plan
Ministry of Education and Universities of the Region of Murcia (Spain)

Ministerio De Educacion Y Ciencia: Rectas Notables De Un Triangulo

For Teachers 9th - 10th Standards
In Spanish. Interactive activities dealing with the concept of angle bisector, median and altitude of a triangle. A description of the circumcenter and centroid are given along with a visual representation. [Requires Java.]
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Activity
Ministry of Education and Universities of the Region of Murcia (Spain)

Ministerio De Educacion Y Ciencia: Actividades Con Las Rectas De Un Triangulo

For Students 9th - 10th
You will find an interactive activity to review the following concepts: altitude, median, angle bisector and points of concurrency in triangles. Five different interactive quizzes are also provided to test your knowledge.
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Activity
Maths Challenge

Maths challenge.net: Triangle Medians

For Students 9th - 10th
Prove that the centroid, P, splits each median into the ratio 2:1. If you give up, then in the top right corner, you may reveal the solution.
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Activity
Texas Instruments

Texas Instruments: Exploring the Centroid of a Triangle

For Teachers 9th - 10th
In this activity, students investigate what happens when all three medians of a triangle are drawn. They learn how to locate the centroid. [Requires Adobe Reader.]