Curated OER
Constructions of Isosceles and Equilateral Triangles
Learners explore the difference between drawing and constructing a triangle utilizing The Geometer's Sketchpad on the computer. They create, develop and script constructions for both isosceles and equilateral triangles. Each student has...
Curated OER
Triangle worksheets
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
Curated OER
Triangles in Architecture
Students find triangles in the real world. In this geometry lesson, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
Curated OER
The Sierpinski Triangle
Students investigate the Sierpinski triangle. In this geometry lesson plan, students define fractal curves and its relationship to triangles. They identify repeating sequences and relate it to fractals.
Curated OER
Congruent Triangles Postulates
Students discover three lettered postulates that prove triangles congruent.
Curated OER
Similar Triangles
Ninth graders find the height of every day objects using techniques learned through postulates that allow triangles in a problem to be similar. They calculate the length of a missing side and solve proportions.
Curated OER
Proofs
In this geometric proof worksheet, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students use given...
Curated OER
Analyzing Congruence Proofs
Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...
Concord Consortium
Short Pappus
It's all Greek to me. Scholars work a task that Greeks first formulated for an ancient math challenge. Provided with an angle and a point inside the angle, scholars develop conjectures about what is true about the shortest line segment...
Curated OER
The Centroid of a Triangle
Students familiarize themselves with the construct and measure menus. They demonstrate how to use the Sketchpad Calculator. They draw a triangle and construct the centroid. They shade in each of the small triangles and measure the area.
Curated OER
Constructing Midsegments of Triangles
Students construct midsegments. In this geometry lesson, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.
Curated OER
Investigating Trigonometric Ratios Through Similar Right Triangles.
49Students investigate the properties of right triangles. In this geometry lesson, students differentiate between similar and congruent triangles. They use the Pythagorean Theorem to find the missing angles and sides.
Curated OER
Investigating Trigonometric Ratios Through Similar Right Triangles
Students identify similar and congruent right triangles. In this geometry lesson, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.
Curated OER
Investigating the Sierpinski Triangle
Students solve and analyze the sierpinski's triangle. In this geometry lesson, students identify properties and theorem of triangles. They solve problems involving angles and sides of triangles.
Curated OER
Proving Triangles Congruent
Students examine Triangle Congruency. For this measurement comparison lesson, students use inductive, deductive and analytical thinking skills to prove triangle congruency. Students analyze and record their findings on activity worksheets.
Curated OER
Pythagorean Theorem
Eighth graders draw right triangles and identify the parts of a right triangle: right angle, interior and exterior angles, hypotenuse and legs. They predict and identify any relationships that exist between the sides of a right...
Curated OER
Altitudes and Orthocenters: Making Connections to the Nine-Point Circle
Students practice various equations for constructing nine-point circles for triangles.
Mathematics Vision Project
Module 3: Geometric Figures
It's just not enough to know that something is true. Part of a MVP Geometry unit teaches young mathematicians how to write flow proofs and two-column proofs for conjectures involving lines, angles, and triangles.
Inside Mathematics
Rhombuses
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
Curated OER
Conjectures and Conclusions
Learners draw conclusions and make conjectures given a specific scenario. In this geometry lesson plan, students model real life scenarios using properties of triangles. They model number facts and explain why the outcome is what it is.
EngageNY
Analytic Proofs of Theorems Previously Proved by Synthetic Means
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....
Mathematics Assessment Project
Evaluating Statements About Length and Area
Class members complete an assessment task by identifying whether statements about triangles and quadrilaterals are always true, sometimes true, or never true. They then participate in a sorting activity with the same objective.
Key Curriculum Press
Triangle Inequalities
Properties about triangles are explored in this lesson. Geometers make conjectures about the length of a triangle's sides, the length of the angles in relation to the length of the sides, and the measure of the exterior angles of a...
Curated OER
Triangles
In this geometry activity, 10th graders solve problems involving triangular inequality. They apply the proofs and theorem of triangles to solve these problems. There is an overview and one question.