Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of activity, 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 triangles.
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...
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
Similar Triangles - Applied Problems
Students differentiate between similar and congruent triangles. In this geometry lesson, 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
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
Students 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 importance of...
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
Mathematical Modeling
Study various types of mathematical models in this math lesson plan. 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...
Curated OER
Triangle Congruence
Learners use web applet to create congruent triangles. For 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
Learners find triangles in the real world. For this geometry lesson, 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, students differentiate between similarity and congruence as they observe polygons. They investigate properties of two and three dimensional shape.
Curated OER
Applications, Proportions, and Problem Solving
In this math worksheet, students find the solutions to the problems involving proportions. They also compare the similar triangles.
Curated OER
Constructing Midsegments of Triangles
Young scholars construct midsegments. In this geometry lesson, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.
Cornell University
Bridge Building
Bridge the gaps in your knowledge of bridges. Individuals learn about bridge types by building models. The activity introduces beam bridges, arch bridges, truss bridges, and suspension bridges.
Curated OER
Pythagorean Theorem
Students identify a right angle and right triangle. They perform WebQuests searching for similar figures and solve for the length of one of the sides given the other two.
Curated OER
Pythagorean Theorem
Students are introduced to the Pythagorean theorem. They use three different activities that give students the opportuntiy to observe triangles, and use the Pythagorean theorem and practice different ways of determining areas of...
Discovery Education
Exploring Geometry
Middle schoolers construct a three-dimensional model of a city using both similar and congruent figures and geometric transformations. City must have at least ten buildings with each building labeled and may be constructed out of paper...
Curated OER
How to weigh a tree
Students pick a tree they see everyday. They measure the tree's circumference and estimate its height using similar triangles. Students are introduced to Computational Science. They use computers and calculators to compute values...
Curated OER
Trig River
Learners calcute distances using trigonometry and angle measurements. They estimate the width of the Trig River, measure it and compare their results with their classmates. They collaborate with a group to research and find the results.
Improving Measurement and Geometry in Elementary Schools
Rep Tiles
In addition to the catchy title, this lesson plan provides upper graders an opportunity to more closely scrutinize the attributes of plane figures. In particular, they focus on the similarity of different shapes. Both whole-class and...