Curated OER
Triangles Congruency Theorems
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry instructional activity, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles...
Curated OER
Inscribing a Circle in a Triangle
Pupils investigate inscribing a circle in a triangle. They use Cabri Jr. to draw a triangle, locate the incenter, and use the distance from the incenter to a side of the triangle to inscribe a circle. The dynamic nature of the geometry...
Curated OER
Triangle Sum Theorem
Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two...
Curated OER
Exploring Centers of a Triangle: Part 1
Learners use problem solving skills, formal geometry, and The Geometer?s Sketchpad. They model and solve two real-world problems by constructing the in center and circumcenter of triangles.
Mathematics Vision Project
Geometric Figures
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...
Curated OER
Gougu Rule or Pythagoras' Theorem
Fifth graders explore Pythagoras' Theorem. They examine the pattern linking the length of the hypotenuse of a right angled triangle and the length of the other two sides. Students find an unknown side in right angled triangles.
Curated OER
Exploring the Witch of Agnesi
students construct the graph of the Witch of Agnesi, and investigate both its asymptotes and inflection points. They construct the graph of the Witch of Agnesi and conjecture the asymptotes and inflection points of the function. ...
Curated OER
I'm So Sorry I Ate Chocolate
Sixth graders investigate the magnitudes of the sides and angles of a triangle. They determine the proof of the Sine Rule before using it to solve triangles. They compare the Sine Rule to the Cosine Rule in this unit of lessons.
Curated OER
The Pythagorean Theorem Lesson 2
Learners discuss and review examples of the Pythagorean Theorem using a GSP, Geometer's Sketchpad, activity.
Curated OER
Connecting Formulas Related to Geometric Figures
Students identify diagrams of quadrilaterals and circles by different names and classify the figures. They name the areas for each diagram and practice solving the formulas for each.
Curated OER
Studying Special Segments in Triangles
Students investigate special segments in triangles. In this geometry lesson, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.
Curated OER
Incenter of a Triangle
Tenth graders explore the properties of the incenter of a triangle. In this geometry lesson, 10th graders construct a triangle and the angle bisectors of each angle. The dynamic properties of Cabri Jr. allow students to locate and...
Curated OER
Exploring Special Segments in Triangles
Students discover that four special segments have a common intersection point. They identify the position of the intersection point in triangles. They produce conjectures about areas of the divided triangles.
Curated OER
Polygon Sum Conjecture
Students calculate the sum of the angles of a polygon. In this geometry lesson plan, students use the interior angle formula of polygon based on the number of sides of the polygon. They identify the missing angle using algebra.
Curated OER
Trina's Triangles
Practice evaluating polynomial expressions at the same time you find Pythagorean Triples. Look for patterns and find examples when the "formula" does and doesn't work. Finally, verify the formula by proving the identity true.
Curated OER
Dilations with Matrices
Examine dilation with matrices with your class. Learners write a conjecture for how the scale factor determines the size of an image. They then use their conjecture to write a matrix multiplication problem for the illustrated triangle...
Education Development Center
Proof with Parallelogram Vertices
Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional students to frame their responses.
Curated OER
Finding the Area of Shapes
In this area of shapes unit, upper graders participate in hands-on problem solving activities to find the formulas for the area of a parallelogram, a triangle, and a trapezoid. They manipulate the geoboard to explore relationships among...
Curated OER
Challenge: Skills and Applications Lesson 2.4
In this algebra worksheet, students create arguments using conjectures. They identify the sequence and the pattern and formula. They solve products and prove sum of integers. There are 8 questions.
Curated OER
Math: Equal Area Triangles
Young scholars examine a math worksheet and determine how to divide a single triangle into four of equal area. Using geometric principles, they sketch two additional ways to divide into into four equal triangles. To conclude, students...
Curated OER
Inductive and Deductive Reasoning
Students use logical arguments and inductive reasoning to make or disprove conjectures. After observing a teacher led demonstration, students discover that the deductive process narrows facts to a few possible conclusions. In groups,...
Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this lesson.
Utah Education Network (UEN)
It's All Just Similar to Me
Middle schoolers explore the concept of similar figures. In this similar figures lesson, pupils calculate scale factors of similar triangles. They find missing sides of triangles, and measure angles using protractors and measure sides of...