EngageNY
Unknown Angle Proofs—Proofs of Known Facts
Lead the class in a Greek history lesson plan with a geometric twist. Pupils relate a short video about geometric properties to modern-day methods of solving for unknown angles. They discuss parallel line theorems and complete practice...
Illustrative Mathematics
The Geometry of Letters
Use the alphabet as a tool for teaching your class about geometric figures. Break apart capital letters into line segments and arcs. Classify angles as right, acute, or obtuse. Identify parallel and perpendicular lines. An excellent...
Curated OER
Points, Lines, Planes, and Space
In this points, lines, planes, and space worksheet, high schoolers solve word problems dealing with points, lines, planes, and space. Students complete 20 individual problems and 20 group problems.
Curated OER
Missing Angle Measures
In this missing angle measures instructional activity, students subtract the angle that is given from 180' to find the missing angle measure. Students complete 6 problems.
Curated OER
Angles
Learners identify obtuse and acute angles in comparsion to a right angle. They identify obtuse, acute, and right angles. Pupils use "Shape Measure" to construct obtuse, acute, and right angles. They review line segements to locate right...
Curated OER
Dividing Line Segments into n Congruent Parts
Learners identify lines, and line segments. For this geometry lesson, students divide line segments into equal congruent parts. They complete a laboratory activity dealing with lines and segments.
Curated OER
Lines, Segments, and Rays
Fifth graders use their arm, toothpicks, and marshmallows to create lines, segments, and rays. In this lines, segments, and rays lesson plan, 5th graders learn how these appear on a plane.
Concord Consortium
Short Pappus
It's all Greek to me. Scholars work a task that Greeks first formulated for an ancient math challenge. Provided with an angle and a point inside the angle, scholars develop conjectures about what is true about the shortest line segment...
Curated OER
Angles in Circles
In this angles in circles activity, 10th graders solve 10 different problems that include tangents and chords and intersecting chords. First, they find x when given 2 intersecting chords. Then, students determine x given the diameter...
Curated OER
Tangents, Secants, and Chords
In this tangents, secants and chords activity, 10th graders identify and solve 48 different problems that include using 3 different theorems for defining circles. First, they determine the area of each circle with C as the center and a...
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
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...
Illustrative Mathematics
Shortest Line Segment from a Point P to a Line L
One of the hardest skills for many young geometers to grasp is to move beyond just declaring obvious things true, and really returning to fundamental principles for proof. This brief exercise stretches those proving muscles as the class...
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...
Curated OER
Lines and Angles
Sixth graders explore lines and angles. They create visual representations of lines, rays and angles by drawing them on paper and using a geoboard. On paper, 6th graders write a summary of the characteristics of their representations.
Curated OER
Lines and Angles
In this math worksheet, students find the information concerning the line segments and angles. They define the complimentary and supplementary angles.
Curated OER
Points, Lines, Segments, Rays, and Angles
In this geometry instructional activity, 5th graders label the two figures shown. Worksheet reviews and provides examples of a point, parallel lines, angles, rays, line segments, and perpendicular lines.
Curated OER
Parallel Lines and Proportional Parts
In this parallel lines and proportional parts worksheet, 10th graders solve 5 different problems related to determining whether lines are parallel and proportional in each figure. First, they refer to the figure shown at the top to...
Curated OER
Geometry: Lesson 1: Points, Lines, Segments, Angles
Fourth graders examine the concepts of, draw, and label points, lines, segments, and angles, They draw, label, and identify horizontal, vertical, intersecting, parallel, and perpendicular lines. They complete an associated worksheet that...
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
Midpoint of a Segment
Learners revisit midpoint and segments by graphing on the TI or computer. This activity can be done with pencil and paper, but is more interactive if it is done on a TI-navigator.
Curated OER
Lines, Rays, Line Segments, and Planes
Students are introduced to lines, rays, line segments and planes and study the differences between them. They also practice graphing lines, rays, line segments and planes
Curated OER
Measuring Angles & Segments
Students view a PowerPoint for a warm-up lesson. They practice measuring around the classroom, measuring such things as the length and width of a desk, pencil, door, and book. Students use a website to practice measuring angles.