Curated OER
Similar Triangles and Proportions
Pupils investigate similar triangles and proportions as they make conjectures about the length of sides of similar triangles. For this lesson plan, have your class construct similar triangles using Cabri Jr so that they share a common...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
EngageNY
The Definition of Sine, Cosine, and Tangent
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar...
Curated OER
SuperShapes, Part 1; "Tri"ing Triangles
An outstanding lesson on triangles awaits your math scholars. Learners focus on the triangle, which is the strongest of all polygons. They see the role that triangles play in the design of buildings, and learn about triangle...
Curated OER
Corresponding Parts of Similar Triangles
Here is a lesson that has learners take a look at corresponding parts of similar triangles, ratios of similarity, reductions and enlargements. They'll manipulate the scale factor (r) to observe the changes in similar triangles and then...
EngageNY
Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams
First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a...
Curated OER
Nested Similar Triangles
Nested triangles have been created so that they share a common vertex and vertex angle. Learners drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When...
Curated OER
Similarity and Dilations - Discover Properties of Similar Figures
Learners investigate properties of similar figures. In this properties of similar figures lesson, pupils construct similar figures using Cabri Jr. They dilate their figure to create a similar one, and discuss the relationships between...
Curated OER
Similar Triangles - Applied Problems
High schoolers differentiate between similar and congruent triangles. In this geometry instructional activity, students identify the angles of triangles using the similarity theorem. They apply concepts of triangles to the real world.
Curated OER
Exploring Polygons and The Greedy Triangle
Excellent lesson plan! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes),...
Curated OER
Triangle Congruence with Coordinate
Two triangles are displayed on a coordinate plane. Youngsters apply a reflection and a translation to demonstrate their congruence. This exercise makes a terrific tool for teaching these concepts, or a way to assess learning.
Curated OER
Triangle Midsegment
Learn how to calculate the length and midsegments of triangles. Learners differentiate between similar and congruent triangles. They create a spreadsheet with their findings.
Curated OER
Similar Figures
Your class will use a TI calculator to drag vertices of rectangles and triangles to observe what happens to ratios of pairs of sides within each figure. They will apply the definition of similarity to identify similar shapes. The...
Curated OER
Triangles
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
Curated OER
The Truth About Triangles And Proofs
High schoolers engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the...
Curated OER
Types of Triangles
Fifth graders explore the required functions of the Geometer's Sketchpad. Using the computer software, they construct similar triangles and identify them by angles and sides. Students classify triangles. Afterward, they complete problems...
Curated OER
Similar and Congruent Triangles
Students create and classify different types of triangles using an online geo-board. They explore the concepts of similar and congruent as they discover how to draw similar and congruent triangles.
Curated OER
Angles and Similarity
High schoolers identify triangles as similar or congruent. In this geometry lesson, students drag triangles around on the navigator to see the effect of different angles on the shape of the triangle. They discuss angle similarity and...
Curated OER
Mathematical Modeling
Study various types of mathematical models in this math lesson. Learners calculate the slope to determine the risk in a situation described. They respond to a number of questions and analyze their statistical data. Then, they determine...
Curated OER
Ratios of Similar Figures
High schoolers identify the ratios of different triangles. In this geometry lesson, students identify the similarity and differences of triangles. They use the navigator to move the sides of the triangle around.
Curated OER
Congruent Triangles
Students identify properties of triangles. In this geometry lesson, students differentiate between similar and congruent triangles. They use the umber of sides to help define the angle of the polygon.
Curated OER
Triangle Congruence
Students use web applet to create congruent triangles. In this geometry lesson, students differentiate between congruent and similar. They create shapes online and drag those shapes around to create visuals of triangles.
Curated OER
Triangles in Architecture
Students find triangles in the real world. In this geometry lesson plan, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
Futures Channel
Folding Circles
Students investigate properties of circles. In this geometry lesson plan, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.