Curated OER
Exploring the Centroid of a Triangle
Pupils examine the centroid of a triangle as they use Cabri Jr. to construct a triangle and its medians. The dynamic nature of the software allows learners to measure the lengths of the segments in the triangle and conjecture and verify...
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using information about...
Curated OER
Ruler and Compass Constructions
Fourth and fifth graders examine how to construct perpendicular lines and to bisect angles using rulers and compasses in this unit of lessons. They design a number of polygons using these methods.
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...
Illustrative Mathematics
Are They Similar?
Learners separate things that just appear similar from those that are actually similar. A diagram of triangles is given, and then a variety of geometric characteristics changed and the similarity of the triangles analyzed. Because the...
EngageNY
Copy and Bisect an Angle
More constructions! In this third installment of a 36-part series, learners watch a YouTube video on creating door trim to see how to bisect an angle. They then investigate how to copy an angle by ordering a given list of steps.
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 instructional activity has individuals work on an assessment task based on similar triangles, then groups them based on their...
PreKinders
A World of Shapes
There are shapes everywhere you see! Use a presentation about shapes to encourage young learners to find squares, circles, triangles, and rectangles in a series of pictures. One slide shows kids what the shapes look like, and then a...
Curated OER
Constructions of Isosceles and Equilateral Triangles
Pupils 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 to...
Curated OER
Isosceles Triangles
Young scholars identify the properties of an isosceles triangle. In this geometry instructional activity, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
Curated OER
Special Right Triangles
Students identify different types of special right triangles. In this geometry lesson, students differentiate between right triangles and isosceles triangles. they construct the triangles using geometry software and make conjectures...
Curated OER
The Sierpinski Triangle
Learners investigate the Sierpinski triangle. In this geometry lesson, students define fractal curves and its relationship to triangles. They identify repeating sequences and relate it to fractals.
Curated OER
Pascal's Patterned Triangle
Fifth graders receive a brief history of Pascal's triangle. As a class the students construct the first few rows of the triangle. The students are then split into groups where they finish a worksheet identifying the total value of each...
Curated OER
Constructions and Loci
In this constructions and loci worksheet, students create a scale drawing of a running track. They identify the starting positions for a given race. Students bisect angles. They construct an angle trisector. This three page worksheet...
Curated OER
Area of Parallelograms and Triangles
Learners explain the formula for finding the area of a paralellogram and its relation to the area of a rectangle. Finally, they construct the formula for the area of a paralellogram.
Curated OER
Number of Solutions for a Triangle
In this solutions for a triangle worksheet, students use trigonometric ratios to determine the number of triangles that can be constructed with the given sides and angles. This one-page worksheet contains 22 problems.
Curated OER
Concurrent Lines in Triangles
Students explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Students use a...
Curated OER
Identify triangles
Students explore triangles. In this geometry instructional activity, students will create note cards with pictorial depictions of right, acute,obtuse, scalene, isosceles, equilateral and equiangular triangles. Students will verbally...
Curated OER
Triangle Worksheet: Cut, Construct and Think 1
In this triangle worksheet, 6th graders draw and cut out a triangle, cut it into three pieces, then arrange the pieces to make new shapes.
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
Testing For Congruent Triangles
Students define and discuss congruency and the corresponding parts between congruent triangles. They create a pair of congruent triangles, test for congruency, and complete a worksheet.
Curated OER
Types of Triangles
Students classify triangles by the length of their sides. In this geometry lesson, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
Curated OER
Let's Explore the World of Triangles and Quadrilaterals!
Second graders explore the features of triangles and quadrilaterals. In this lesson on triangles and quadrilaterals, 2nd graders rotate with their group to five different activities all exploring a different aspect of geometry.
Curated OER
Triangles and Quadrilaterals
Second graders explore triangles and quadrilaterals. They rotate to various centers in the room to identify and examine triangles and quadrilaterals. After presenting a picture to the class, 2nd graders locate right angles, triangles...