CK-12 Foundation
Bisectors of Line Segments and Angles: Cut an Angle
Explore constructions through an interactive online lesson. Given an example of an angle bisector construction, learners investigate the markings to determine the method used. Challenge questions help solidify the steps.
CK-12 Foundation
Bisectors of Line Segments and Angles: Cut a Line
Geometric constructions build relationships —by simply manipulating simple tools. An interactive lesson presents a completed construction of a segment bisector and has learners analyze the important aspects. Ultimately, they should be...
Curated OER
Altitude, Median, and Angle Bisector of a Triangle
Learners investigate the special properties of an altitude, a median, and an angle bisector and explore how these special segments divide the area of a triangle. The dynamic nature of Cabri Jr. allows pupils to form and verify conjectures.
Concord Consortium
Detective Stories
The truth will always come out. A short performance task has learners considering a witness statement given to a detective. They apply special line segments in triangles and Ceva's Theorem to prove that the witness is actually lying.
Curated OER
Special Segments in Triangles
Young scholars identify important properties of triangles. In this geometry lesson, students differentiate between medians, bisectors and altitudes in a triangle. They identify the properties of these important segments.
Curated OER
Constructing Perpendicular Bisectors
Tenth graders investigate parallel lines and the angles formed when cut by a transversal. In this geometry lesson plan, 10th graders construct perpendicular lines and discuss midpoint, segments and perpendicular bisectors. They relate...
Curated OER
IGD: Perpendicular Bisector
Students draw perpendicular bisectors. In this perpendicular bisectors lesson, students identify the perpendicular bisector in a polygon. They use web tools to create and measure perpendicular bisectors. Students identify lines of...
Curated OER
Inscribed Angles
Students calculate the inscribed angle of a triangle. For 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
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
Studying Special Segments in Triangles
Learners investigate special segments in triangles. In this geometry instructional activity, students graph, compare, estimate and predict findings based on their data. They differentiate between similarity and congruence of triangles.
Concord Consortium
In Oz We Tryst
The shortest distance from point A to point B is a straight line, but measuring distance gets more complicated when there are three points! Given the location of three friends, individuals determine the best point for all three friends...
Curated OER
Cabri Jr. Perpendicular Bisector of a Chord
Your learners will construct the perpendicular bisector of a chord. They use Cabri Jr. to construct a circle and a perpendicular bisector of a chord. They then measure lengths of the chords and perpendicular bisectors. Learners use...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
EngageNY
Characterize Points on a Perpendicular Bisector
Learn transformations through constructions! Pupils use perpendicular bisectors to understand the movement of a reflection and rotation. They discover that the perpendicular bisector(s) determine the line of reflection and the center of...
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...
Curated OER
Isosceles Triangles
Young scholars 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.
EngageNY
Designing a Search Robot to Find a Beacon
Build right angles using coordinate geometry! Pupils explore the concept of slope related to perpendicular lines by examining 90-degree rotations of right triangles. Learners determine the slope of the hypotenuse becomes the opposite...
Curated OER
Constructing Perpendiculars
Young scholars construct perpendicular lines. In this geometry lesson, students use a compass and straight edge to do construction. They start from a point to a line.
Curated OER
Contructions and Conjectures
Students make constructions and conjectures. In this geometry lesson, students construct right, acute and obtuse angles using a straight edge and a protractor. They investigate parallel lines and the angles formed by the angles.
Curated OER
Concurrent Lines in Triangles
Students explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Students use a...
Curated OER
Exploring Geometric Mean
Students solve problems using geometric means. In this geometry lesson, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
Curated OER
Exploring Geometric Mean
Student identify the solution using geometric mean. For this geometry lesson, students create right triangles where the altitude of the triangle is the side containing the right angle. They modify shapes using Cabri software and observe...
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
Investigating Trigonometric Ratios Through Similar Right Triangles
Students identify similar and congruent right triangles. In this geometry lesson, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.