Curated OER
Analyzing Congruence Proofs
Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...
CK-12 Foundation
Basic Trigonometric Functions: Ladder Length
Climb the ladder to trigonometry. The interactive introduces trigonometric ratios and finding lengths of sides of right triangles created by a ladder and a building. Learners use the interactive to create triangles by moving the top of...
CK-12 Foundation
Pythagorean Theorem to Determine Distance: Ladders
Young mathematicians to the rescue! Pupils use an interactive to find lengths relating a ladder against a building. The problems involve determining how long a ladder must be to reach a given floor to what floor can a given ladder reach.
Illustrative Mathematics
Solar Eclipse
Learners take on the role of astronomers, calculating conditions necessary for a total solar eclipse. Concepts of similar triangles and properties of circles come together as pupils create ratios and use real measurements in determining...
Curated OER
Triangle Congruence
In this triangle congruence worksheet, 10th graders solve 12 different problems that include determining triangle congruence. First, they prove that triangles are either congruent or similar. Then, students determine whether they can...
EngageNY
Systems of Equations Leading to Pythagorean Triples
Find Pythagorean Triples like the ancient Babylonians. The resource presents the concept of Pythagorean Triples. It provides the system of equations the Babylonians used to calculate Pythagorean Triples more than 4,000 years ago. Pupils...
EngageNY
Congruence, Proof, and Constructions
This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs. Each of the almost-forty lessons is broken...
Curated OER
Similar Triangles on the Coordinate Plane
Young scholars investigate triangles and their properties. In this geometry lesson plan, students differentiate between similar and congruent triangles. They use the SSS theorem to help identify the triangles that are similar or congruent.
Mathed Up!
Angles: Parallel Lines
Viewers are presented with seven problems with parallel lines and angle relationships and must use the given information to find the measures of specific angles. To finish, they explain their process in finding the measures in the problems.
Curated OER
Areas of Geometric Shapes with the Same Perimeter
A triangle, square, hexagon, and circle all have a perimeter of one unit. Eighth graders must attempt to find the area of each and arrange them in order from least to greatest areas. A terrific task for applying four different area...
Lane Community College
Review Sheets: Geometry
Full of problems with polygons, angles, lines, and triangles, your learners get a multi-page packet that provides all they need to know. It contains many of the standard problem types as well as some more challenging questions.
Curated OER
Side Splitter Triangles
Students investigate the side splitter theorem. In this geometry lesson plan, students estimate and solve problems dealing with ratios and proportions. They identify angles created by lines that are parallel.
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
Investigating Trigonometric Ratios Through Similar Right Triangles.
49Students investigate the properties of right triangles. In this geometry lesson, students differentiate between similar and congruent triangles. They use the Pythagorean Theorem to find the missing angles and sides.
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.
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
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
Similar Polygons Multiple Choice
In this geometry worksheet, students differentiate between similarity and congruence. They find the correct answer using the theorems of similarity and congruence. There are 5 questions with an answer key.
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.
EngageNY
Criterion for Perpendicularity
The Pythagorean Theorem is a geometry pupil's best friend! Learners explain the equation a1b1 + a2b2 = 0 for perpendicular segments using the Pythagorean Theorem. They are able to identify perpendicular segments using their endpoints and...
Teach Engineering
Catching the Perfect SAR Waves!
Zero in on an interesting resource involving radar technology. Groups construct a radar sensing unit and learn to calibrate the system. Using the radar system and the Pythagorean Theorem, they calculate distances between objects.
Mathematics Assessment Project
Evaluating Statements About Length and Area
Class members complete an assessment task by identifying whether statements about triangles and quadrilaterals are always true, sometimes true, or never true. They then participate in a sorting activity with the same objective.
EngageNY
General Pyramids and Cones and Their Cross-Sections
Are pyramids and cones similar in definition to prisms and cylinders? By examining the definitions, pupils determine that pyramids and cones are subsets of general cones. Working in groups, they continue to investigate the relationships...
Curated OER
Similar triangles
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...