EngageNY
Similar Triangles in Circle-Secant (or Circle-Secant-Tangent) Diagrams
First angle measures, now segment lengths. High schoolers first measure segments formed by secants that intersect interior to a circle, secants that intersect exterior to a circle, and a secant and a tangent that intersect exterior to a...
Alabama Learning Exchange
Mirror, Mirror on the Wall: Reflections of Light
Why can we see our reflection in a window but not a brick wall? Young physicists learn the Law of Reflection and various light properties that help them answer this and other questions about reflection. Use the PowerPoint to introduce...
Curated OER
Exploring Characteristics of Triangles
Students draw triangles and explore the classification of each using the measures of interior angles and lengths of sides. They investigate the sum of the interior angles of various triangles and conjecture and prove the theorem: The...
EngageNY
Rotations
Searching for a detailed lesson to assist in describing rotations while keeping the class attentive? Individuals manipulate rotations in this application-based lesson depending on each parameter. They construct models depending on the...
Curated OER
Perpendicular Bisector of a Line Segment
High Schoolers investigate the perpendicular bisector of a line segment. They use Cabri Jr. to construct the perpendicular bisector of a segment. The dynamics capabilities of Cabri Jr. allow your learners to observe the lengths of the...
Curated OER
Circles and Angles
Young scholars identify tangents, chords and secants. In this geometry activity, students graph circles and identify angles created by secant lines, tangent lines and chords.
Curated OER
Special Segments in a Triangle
In this geometry worksheet, 10th graders review the vocabulary associated with the special segments of a triangle and the associated points of concurrency and solve problems in which they find the indicated missing angle or segment. The...
Curated OER
Inscribed Angles
Students calculate the inscribed angle of a triangle. In this geometry lesson, students identify the angle created by intersection of a triangle and a circle. They see the relationship between the arc and the angle.
Curated OER
Exploring Angle/Pair Relationships
Students find missing angles and sides of triangles. In this geometry lesson, students create intersecting lines to measure angles. They use Cabri Software to create virtual angles.
Curated OER
Geometry and Measurement
Students view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Students use pegboards and string to create more...
West Contra Costa Unified School District
Parallel Lines Cut by a Transversal
Parallel lines seem so right for each other. It's too bad they'll never, ever meet. Learners use tracing paper to discover relationships among angles formed by two parallel lines cut by a transversal. They apply this information to find...
Curated OER
Measurement of a Central Angle
Students calculate the measurement of a central angle. In this geometry lesson, students identify properties of circles. They use Cabri software to create and analyze graphs.
Curated OER
Duplicating Segments and Angles
Tenth graders investigate geometric construction. In this geometry lesson, 10th graders explore the procedure for copying an angle and a segment. The lesson emphasizes the difference between a sketch, a drawing, and a construction and...
Curated OER
Introducing Angles
Sixth graders identify, compare and interpret the characteristics of polygons and angles in order to meet spatial sense, geometry and measurement standards. They also sort shapes into three categories, polygons (regular and irregular)...
Curated OER
Dividing Line Segments into n Congruent Parts
Students identify lines, and line segments. In this geometry lesson plan, students divide line segments into equal congruent parts. They complete a laboratory activity dealing with lines and segments.
Curated OER
Exploring Harmonic Conjugates
High schoolers investigate harmonic conjugates using Cabri Software or the Ti Calculator to analyze harmonics. They explore different angles measurements as they move their circles around and solve problems.
Curated OER
Bisecting Angles and Segments
Young scholars bisect angles and segments using a mira. They measure the original angles and segments and the angles and segments formed by bisecting to better see the relationship between them.
Curated OER
Searching for Angles and Lines
Students work to find and reinforce concepts related to lines and angles. They identify the characteristics of shapes that have one, two, and three dimensions. The students also work on definitions related to the geometry of shapes.
Curated OER
New Angle on Forest Ecology
Students measure and calculate the angle of the sun. They compare the leaf types on the north and south to compare the effects of the sun on the type of vegetation. They complete the activities inside the classroom or on a trip to a...
Curated OER
Exploring Angle Pair Relationships
Students investigate the relationship between angles of triangles. In this geometry lesson plan, students identify properties of right and non-right triangles. They differentiate between vertical and supplementary angles.
Curated OER
The Trig To Soccer
Students are given the background information to open the lesson: Suppose a penalty kicker in soccer could choose where he could kick from, as long as he stayed on the back line of the penalty area. Would he have a better chance of...
Virginia Department of Education
How Many Triangles?
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the same...
Curated OER
Arc Measurement Based on The Measurement of a Central Angle
Students define keywords that are important to solve problems. In this geometry instructional activity, students find the arc length and angle of a circle. They convert between radians and degrees.
Curated OER
Studying Special Segments in Triangles
Students investigate special segments in triangles. In this geometry lesson, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.