Lesson Plan
Curated OER

Pedal Triangles

For Teachers 8th - 10th
Pupils identify the properties and theorems of triangles. In this geometry lesson, students construct angle bisectors using a compass and straight edge. They identify triangular similarity and congruency.
Worksheet
Curated OER

Triangle Proofs

For Students 9th - 12th
In this triangle proofs learning exercise, students answer 5 questions about triangles and polygons given certain information. Students then construct 4 triangle or polygon proofs.
Lesson Plan
EngageNY

Similarity and the Angle Bisector Theorem

For Teachers 9th - 10th Standards
Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...
Assessment
Charleston School District

Review Unit 2: Congruence and Similarity

For Students 8th Standards
Review for the test with a comprehensive list of terms and concepts for the unit on congruence and similarity. It divides divides the sections in the order of the lessons presented during the unit. 
Activity
K-5 Math Teaching Resources

Tangram Cutout

For Students K - 5th Standards
Challenge the spatial thinking of your young mathematicians with this printable tangram puzzle. Using different sized triangles, squares, and parallelograms, children must figure out how to fit all the shapes together to create a square.
Unit Plan
Radford University

Parallel Lines Cut by a Transversal

For Teachers 9th - 12th Standards
Use the parallel lines to find your way. After first reviewing geometric constructions and the relationships between angles formed by parallel lines and a transversal, young mathematicians write proofs for theorems relating to parallel...
Unit Plan
Radford University

Building a House

For Teachers 9th - 12th Standards
Ever dream of becoming an architect? Here's your chance to give it a try. After reviewing facts about triangles and quadrilaterals, pupils learn about the basics of architecture by talking to an architect or housing expert. They use...
Activity
Noyce Foundation

Poly-Gone

For Students K - 12th Standards
Investigate polygons from rectangles to triangles to octagons. Each level of the five-problem series targets a different grade level. Beginning with the level A problem, learners examine the relationship between area and perimeter by...
Unit Plan
Curated OER

Transformations in the Coordinate Plane

For Teachers 9th - 12th Standards
Your learners connect the new concepts of transformations in the coordinate plane to their previous knowledge using the solid vocabulary development in this unit. Like a foreign language, mathematics has its own set of vocabulary terms...
Worksheet
1
1
Math Wire

Gingerbread Man Combinations

For Students 4th - 8th
Gingerbread men are just like us—they're unique! Discover how many combinations are possible when constructing a gingerbread man with several choices for shapes and colors of eyes, noses, and buttons. 
Worksheet
Curated OER

Constructions and Loci

For Students 9th - 10th
In this geometry worksheet, students construct polygons and calculate the different angles formed by each shape. They construct circles, trapezoids, and rectangles and answer 20 questions.
Lesson Plan
Key Curriculum Press

Triangle Inequalities

For Teachers 8th - 11th Standards
Properties about triangles are explored in this lesson. 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...
Lesson Plan
Curated OER

Triangle Town

For Teachers 2nd
Second graders create a fact family town to develop the understanding of numbers related in fact families. They learn each family has a big number and two baby numbers. They make triangle shaped houses for their facts.
Lesson Plan
Curated OER

Angles of a Triangle

For Teachers 9th - 12th Standards
Learners explore the measures of the angles of a triangle in this geometry lesson. They use Cabri Jr. to investigate the sum of the measures of the interior angles of a triangle, and examine the relationships between the interior and...
Lesson Plan
Texas Instruments

Getting Started with Cabri Jr.

For Teachers 9th - 12th Standards
Pupils construct geometric figures using Cabri Jr. in this constructing geometric figures using Cabri Jr. lesson plan. They familiarize themselves with Cabri Jr. and construct segments and triangles. Your learners will use various tools...
Worksheet
Math Mammoth

Construct Line Segments and Angles

For Students 6th - 7th
In this math instructional activity, learners are asked to used a compass and straight edge to construct copies of shapes, angles and line segments.
Lesson Plan
Curated OER

Triangle Conjectures

For Teachers 10th
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
Worksheet
Curated OER

Trigonometric Triangles

For Students 9th - 11th
In this trigonometry worksheet, students find the missing angle and sides given the 6 trigonometric values. There are 6 questions with an answer key.
Lesson Plan
Curated OER

Isosceles Triangles

For Teachers 9th - 10th
Students 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.
Lesson Plan
Curated OER

Pascal's Patterned Triangle

For Teachers 5th
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...
Lesson Plan
Curated OER

The Sierpinski Triangle

For Teachers 9th - 10th
Students investigate the Sierpinski triangle. In this geometry instructional activity, students define fractal curves and its relationship to triangles. They identify repeating sequences and relate it to fractals.
Worksheet
Curated OER

Triangles and Quadrilaterals

For Students 10th
In this triangles and quadrilaterals worksheet, 10th graders solve 6 different problems related to using triangles and quadrilaterals in informal geometry. They determine how many lines of symmetry an equilateral triangle and an...
Lesson Plan
Curated OER

Triangles & Congruence, Proportions & Similarity, Right Triangle & Trigonometry

For Teachers 9th - 12th
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...
Lesson Plan
Curated OER

Roofing and Right Triangles

For Teachers 9th - 11th
Young scholars use models and symbols to represent properties of the Pythagorean Theorem. In this right triangle instructional activity, students connect real jobs to properties of right triangles. They solve word problems applying the...