Curated OER
Triangle Sum Theorem
Teach your class how to solve problems using the triangle sum theorem. In this geometry lesson, students identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides around to create...
Illustrative Mathematics
Alike or Different Game
How are a circle and triangle alike? How are they different? These are the types of questions children will answer while playing this fun geometry game. Including a variety of conventional and unconventional shapes, this activity allows...
Illustrative Mathematics
All vs. Only Some
All shapes have certain defining attributes that set them apart from others. In order to understand this, young mathematicians look at examples and non-examples of triangles, rectangles, and squares, working as a whole class to create...
Curated OER
Reflecting Reflections
A triangle rests in quadrant two, from which your class members must draw reflections, both over x=2 and x=-2. This focused exercise strengthens students' skills when it comes to reflection on the coordinate plane.
Curated OER
Review of Triangles
Students investigate the Pythagorean Theorem. In this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
Curated OER
Classifying Triangles by the Length of the Sides Using Cabri Jr.
Learners follow detailed directions to create triangles on their graphing calculator. In this properties of triangles lesson, they will create triangles on their calculators using the Cabri Jr. application. They then identify three...
Curated OER
Properties of Parallelograms
Young scholars identify different properties of parallelograms. In this geometry lesson, students complete problems that proves the theorems and properties of parallelograms. They graph the different shapes on paper.
Curated OER
Roll It! Creating an Entrance Ramp
Students explore the concept of triangles. In this triangles lesson, students are to propose a plan for a ramp at their school. Students use the Pythagorean Theorem and trigonometry to determine the length, height, and angle of the...
Curated OER
Building With Triangles
Fourth graders use two different techniques to construct triangles with specific dimensions. They determine how to construct nets for three-dimensional objects focusing on those made with equilateral triangles. They are able to name the...
Curated OER
Triangle Exploration
Learners are introduced to The Geometer's Sketchpad software while in the computer lab. They focus on triangles, horizontal lines, vertex and top parallel lines. Each student utilizes geometry to complete basic geometric constructions.
Curated OER
Similar Triangles on the Coordinate Plane
Students investigate triangles and their properties. In this geometry lesson, students differentiate between similar and congruent triangles. They use the SSS theorem to help identify the triangles that are similar or congruent.
Curated OER
Special Segments in Triangles
Students identify important properties of triangles. In this geometry instructional activity, students differentiate between medians, bisectors and altitudes in a triangle. They identify the properties of these important segments.
Curated OER
Investigating Lengths of Segments in a Triangle
Pupils explore the midsegment of a triangle in the geometry lesson. They draw and measure the segment joining the midpoints of the two sides of a triangle and compare its length to the length of the third side of the triangle. The...
Curated OER
Altitude, Median, and Angle Bisector of a Triangle
Learners investigate the special properties of an altitude, a median, and an angle bisector and explore how these special segments divide the area of a triangle. The dynamic nature of Cabri Jr. allows pupils to form and verify conjectures.
Curated OER
Congruent Triangles
Students identify properties of triangles. For 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
Concurrent Lines in Triangles
Students explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson plan, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Students use a...
Mathematics Assessment Project
Deducting Relationships: Floodlight Shadows
Try to figure out what happens with shadows as a person moves between two light sources. A formative assessment lesson has individuals work on an assessment task based on similar triangles, then groups them based on their assessment...
EngageNY
Modeling Using Similarity
How do you find the lengths of items that cannot be directly measured? The 13th installment in a series of 16 has pupils use the similarity content learned in an earlier resource to solve real-world problems. Class members determine...
Illustrative Mathematics
Extensions, Bisections and Dissections in a Rectangle
Gaining practice in translating a verbal description into a diagram and then an equation is the real point of this similar triangles exercise. Once the diagram is drawn, multiple methods are provided to reach the conclusion. An effective...
Curated OER
Properties of Triangles
Students explore the relationship between how big a side of a triangle is and how big its opposite angle is by creating triangles using an interactive website.
Curated OER
Triangles & Congruence, Proportions & Similarity, Right Triangle & Trigonometry
Students are introduced to the topic of congruence and proportions in Geometry. Using technology, they construct and validate the properties of various geometric figures and identify whether it is congruent or proportion to the objects...
Curated OER
Let the Matrix Do It
Students create a matrix of the vertices of a triangle and produce new matrices that dilate, translate, rotate, and reflect the original triangle. After multiplying each matrix by a new scale factor, they graph the new matrix and...
Curated OER
Equilateral Triangles
Students examine the attribute of equilateral triangles. In this equilateral triangle lesson, students examine a number of paper triangles to determine how they are classified. They determine how triangles are depicted in Navajo rugs.
Curated OER
Triangle Inequality Theorem
Students identify properties of triangles. In this geometry lesson, students create triangles using three different segments. They make conjectures and predictions.