Curated OER
Math: Investigating Triangles
Tenth graders identify the trigonometric ratios for right angled triangles. Through independent investigation, they discover the constancy between the ratios of any two sides of similar triangles. In an alternative method, 10th graders...
Las Cumbres Observatory
The Cosmic Distance Ladder: Parallax
Scientists don't have a ruler long enough to measure to the stars, so they rely on math. Scholars learn to calculate the distance from Earth to a star using the parallax method. They use angle measures from different perspectives to...
Curated OER
CSI Investigation of Congruence and Similarity
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
Curated OER
Why can't We Use SSA to Prove Triangles Congruent?
Students investigate triangles and congruences. In this geometry instructional activity, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
Pennsylvania Department of Education
Making Triangles
Learners use interactive geoboards to identify simple geometric shapes. In this making triangles lesson plan, students describe the properties associated with geometric shapes. Learners develop spatial sense and the mathematical meaning...
Curated OER
Investigating the Sierpinski Triangle
Students solve and analyze the sierpinski's triangle. For this geometry lesson, students identify properties and theorem of triangles. They solve problems involving angles and sides of triangles.
Curated OER
Pedal Triangles
Students identify the properties and theorems of triangles. In this geometry lesson plan, students construct angle bisectors using a compass and straight edge. They identify triangular similarity and congruency.
Curated OER
The Minimal Distance Point from the Vertices of a Triangle
Students calculate the distance from the vertex of a triangle to the center. In this geometry lesson, students find the shortest distance between a point and the vertex of a triangle. They relate this concept of distance to the real world.
Curated OER
Exploring Characteristics Needed to Prove Two Trianlges Congruent
Tenth graders explore congruent triangles. In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles congruent. The lesson combines dry erase board activities and the use of technology.
Curated OER
Geometry Scavenger Hunt
Students hunt for hidden geometric shapes and compare the properties of various shapes. In this geometry lesson, students play a game of finding squares, circles, rectangles, and ovals that have been hidden around the classroom. Students...
Curated OER
Three- and Two- Dimensional Geometry
In this three- and two- dimensional geometry worksheet, 7th graders solve 12 various problems related to geometric shapes and measurement. They first use paper and a pencil to sketch the front, side, back, top and bottom views of each...
Curated OER
Congruent Trianges - Is This Enough Information?
Seventh graders determine whether two triangles are congruent and provide an explanation to why they are not. They apply concepts of measurement of angles and collect evidence of congruent angles in the world.
Key Curriculum Press
Triangle Inequalities
Properties about triangles are explored in this activity. 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
Physical Properties of Matter
Students examine the physical properties of matter. They identify and classify a variety of objects based on their physical properties.
Curated OER
Congruent Triangles - Is This Enough Information?
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
Curated OER
Dihedral Figures
Middle and high schoolers perform transformations. In this web based lesson, students explore dihedral figures. They use the web tools to translate, rotate, and reflect figures. Pupils identify lines of symmetry.
Curated OER
Does Your Field Measure Up
Students measure angles using a plane table kit. In this geometry instructional activity, students use trigonometric identities to find the values of the length of a football field.
CK-12 Foundation
Sequence of Partial Sums: Partial Sums
Have some fun building squares out of triangles. Pupils investigate the partial sums of odd numbers. Using the sum of the first four odd numbers, learners see that it can be rewritten as a sum containing a triangular number. Simplifying...
Curated OER
As the Bird Flies
Students investigate the properties of lines and congruent triangle theorems as well as apply geometric properties and relationships to real-world mathematical problems. Given two different scenarios, they examine maps that have been...
101 Questions
Snail's Pace
Time doesn't fly when you're watching a snail cross a sidewalk. Combining the concepts of the Pythagorean Theorem and the distance, rate, and time formula, learners determine how long it takes a snail to go from one corner of a sidewalk...
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...
Curated OER
Classifying Polygons
Students study polygons. In this math instructional activity, students play a game in which they learn the classification system for polygons. Students identify the properties of quadrilaterals.
Curated OER
Designing a Fort
Students explore the concept of right triangles. In this right triangle lesson, students construct a scale model of a tourist attraction similar to Fort Jefferson. Students research aerial photos of Fort Jefferson, then build their...
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...