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
Congruence Criteria for Triangles—AAS and HL
How can you prove it? Guide classes through an exploration of two possible triangle congruence criteria: AAS and HL. Learners connect this criteria to those previous learned and also explore criteria that does not work. The lesson...
Curated OER
Perpendicular and Angle Bisectors
In this geometry worksheet, 10th graders solve problems that are based on the theorems associated with perpendicular and angle bisectors of a triangle. An application on the coordinate plane is included. The one page worksheet contains...
Curated OER
Chapter 5 Final Review Extra Problems. Triangles
In this triangles worksheet, students identify the median, altitude, segment, angle bisector, perpendicular bisector and triangle midsegment of triangles. They find the perimeter of triangles. This three-page worksheet contains 8...
EngageNY
Tangent Segments
What's so special about tangents? Learners first explore how if a circle is tangent to both rays of an angle, then its center is on the angle bisector. They then complete a set of exercises designed to explore further properties and...
Mt. San Antonio Collage
Isosceles Triangles and Special Line Segments
Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...
Curated OER
Transformations in the Coordinate Plane
Your learners connect the new concepts of transformations in the coordinate plane to their previous knowledge using the solid vocabulary development in this unit. Like a foreign language, mathematics has its own set of vocabulary terms...
Mathematics Vision Project
Module 5: Circles A Geometric Perspective
Circles, circles, everywhere! Pupils learn all about circles, central angles, inscribed angles, circle theorems, arc length, area of sectors, and radian measure using a set of 12 lessons. They then discover volume formulas through...
Curated OER
Bisectors of Triangles
In this geometry worksheet, 10th graders solve problems involving the perpendicular bisectors and angle bisectors of a triangle and their points of concurrency. The one page worksheet contains sixteen questions. Answers are included.
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...
Mathematics Vision Project
Module 3: Geometric Figures
It's just not enough to know that something is true. Part of a MVP Geometry unit teaches young mathematicians how to write flow proofs and two-column proofs for conjectures involving lines, angles, and triangles.
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
Ruler and Compass Constructions
Fourth and fifth graders examine how to construct perpendicular lines and to bisect angles using rulers and compasses in this unit of lessons. They design a number of polygons using these methods.
Mathematics Vision Project
Geometric Figures
Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...
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...
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...
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
Geometry Worksheet
In this geometry instructional activity, 10th graders solve for the missing angles using the angles theorems. There are 3 questions asking about angle bisectors and missing angles.
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 16 different types of problems. First, they name the corresponding parts of the congruent triangles shown and draw a picture. Then, students list the five ways to...
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...
Curated OER
Standardized Geometry Test Practice
In this angles, lines and figures review worksheet, 10th graders solve and complete 33 standardized multiple choice problems. First, they use the Segment Addition Postulate to solve for a variable given an equation for each line. Then,...
EngageNY
Triangle Congruency Proofs (part 1)
Can they put it all together? Ninth graders apply what they know about proofs and triangle congruence to complete these proofs. These proofs go beyond the basic triangle congruence proofs and use various properties, theorems, and...
Curated OER
Heron's Formula
Students use Heron's formula to calculate the area of a triangle. In this geometry lesson, students use three different methods to solve the area of a triangle. They find and construct the incentor and angle bisector of a triangle.
Curated OER
Triangle Fundamentals Homework
In this geometry worksheet, students identify the missing angles of non right triangles using the angle sum theorem. They solve for the unknown using algebra. There are 21 questions.