Virginia Department of Education
Lines and Angles
Explore angle relationships associated with transversals. Pupils construct parallel lines with a transversal and find the measures of the angles formed. They figure out how the different angles are related before constructing...
Curated OER
Angles, Lines, and Transversals
Geometers identify and determine angle pair relationships when two parallel lines are intersected by a transversal. They review the concepts of angles by watching streaming video clips online, read definitions of lines and angles from...
Curated OER
Angle Relationships
Students investigate geometric relationship using conjecture about linear pairs and vertical angles. In this geometry lesson, students apply their theorems and previous geometry knowledge to solve for and find angles of linear...
Curated OER
Creating Parallel Lines and Transversals
Have your class create parallel lines. Students will learn how to identify the different angles created by a parallel line cut by a transversal. Then, they identify and name similar and different angles.
Texas Instruments
Points, Lines, and Planes
Young scholars solve problems dealing with points, lines and planes. For this geometry lesson, students differentiate between parallel lines and planes. They find the intersection of lines and planes.
West Contra Costa Unified School District
Arcs and Angles
Noah didn't construct this kind of arc. High school scholars first explore how angles can be formed in circles. They then learn relationships between angles and arcs by conducting an exploratory activity where they position and draw arcs...
EngageNY
Solve for Unknown Angles—Angles and Lines at a Point
How do you solve for an unknown angle? In this sixth installment of a 36-part series, young mathematicians use concepts learned in middle school geometry to set up and solve linear equations to find angle measures.
EngageNY
Angles Associated with Parallel Lines
Explore angle relationships created by parallel lines and transversals. The 13th instructional activity of 18 prompts scholars use transparency paper to discover angle relationships related to transversals. Learners find out that these...
Curated OER
Angle Relationships
Tenth graders explore the angle relationships that exist when two lines intersect. In this geometry lesson, 10th graders estimate the measure of given angles and use their graphing calculator tools. Students use this knowledge to find...
Curated OER
Intersecting Lines and Vertical Angles
Pupils identify and define intersecting lines and vertical angles. They draw two intersecting lines and measure one pair of vertical angles. Learners will also move a line to change the angles of a figure and describe the changes in the...
Curated OER
Circles and Angles
Young scholars identify tangents, chords and secants. In this geometry lesson, students graph circles and identify angles created by secant lines, tangent lines and chords.
EngageNY
Circles, Chords, Diameters, and Their Relationships
A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...
Willow Tree
Angles Formed by Transversals of Coplanar Lines
Create a strong understanding of the relationships formed when parallel lines intersect a transversal. Discuss each type of angle pair and their relationship to each other.
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...
EngageNY
Angle Sum of a Triangle
Prove the Angle Sum Theorem of a triangle using parallel line and transversal angle relationships. Pupils create a triangle from parallel lines and transversals. They find angle measures to show that the angles of a triangle must total...
Curated OER
Alternate Interior Angles
Label angles of parallel lines to analyze the angles created by a transversal and two parallel lines. They graph their lines and observe the similarity and difference in the angles.
EngageNY
Similarity and the Angle Bisector Theorem
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...
EngageNY
Secant Angle Theorem, Exterior Case
It doesn't matter whether secant lines intersect inside or outside the circle, right? Scholars extend concepts from the previous activity to investigate angles created by secant lines that intersect at a point exterior to the...
Curated OER
Triangle Side Lengths and Angles Measures
Students identify missing sides and angles. In this geometry lesson, students use triangular theorems to identify the missing sides. They use the Pythagorean Theorem to find the different ratios of each side.
EngageNY
Unknown Angle Proofs—Proofs with Constructions
Provide your emerging mathematicians with the tools to learn as they incorporate auxiliary lines to solve unknown angle proofs in this continuing segment. They decipher information from a diagram to uncover the missing pieces and...
Virginia Department of Education
Angles, Arcs, and Segments in Circles
Investigate relationships between angles, arcs, and segments in circles. Pupils use geometry software to discover the relationships between angles, arcs, and segments associated with circles. Class members use similar triangles to...
Mathematics Assessment Project
Inscribing and Circumscribing Right Triangles
High schoolers attempt an assessment task requiring them to find the radii of inscribed and circumscribed circles of a right triangle with given dimensions. They then evaluate provided sample responses to consider how to improve...
Curated OER
Angles, Lines and Transversals
Students identify and determine angle pair relationships. In this geometry lesson, students identify different angles of parallel lines that are cut by transversals. They identify interior and exterior angles after watching a video.
Curated OER
Parallel and Perpendicular Lines
Tenth graders explore parallel and perpendicular lines. In this geometry instructional activity, 10th graders investigate the relationships associated with parallel lines and transversals, perpendicular lines, and the angles formed...