Curated OER
Geometry, Measurement & Reasoning
Students construct two-column proofs. In this geometry instructional activity, students use deductive reasoning and geometric properties to justify given geometric statements. Students compare and contrast proofs.
Curated OER
Triangle worksheets
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
Curated OER
Indirect Proof and Inequalities in One Triangle
In this geometry worksheet, 10th graders order the sides and angles of a triangle and determine the range of the third side of a triangle given the lengths of two sides. The one page worksheet contains sixteen questions. Answers are...
EngageNY
Mid-Module Assessment Task - Geometry (Module 1)
How do you prepare class members for the analytical thinking they will need in the real world? An assessment requires the higher order thinking they need to be successful. The module focuses on the concept of rigid transformations...
Illustrative Mathematics
Is This a Parallelogram?
If both pairs of opposite sides of a quadrilateral are congruent, is the quadrilateral a parallelogram? This task asks learners to determine the answer and to support their answer with a proof. The resource includes a commentary for...
Illustrative Mathematics
Midpoints of the Sides of a Paralellogram
This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...
Curated OER
Rotation Symmetry
Students investigate the concept of symmetry by using various examples and performing independent practice with scaffolding provided by the teacher. They review reflection symmetry and cover the new rotation symmetry using manipuatives.
Inside Mathematics
Quadrilaterals
What figure is formed by connecting the midpoints of the sides of a quadrilateral? The geometry assessment task has class members work through the process of determining the figure inscribed in a quadrilateral. Pupils use geometric...
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...
Mathematics Vision Project
Similarity and Right Triangle Trigonometry
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
Radford University
Parallel Lines, Transversals, and Angles: What’s the Connection?
Streets, bridges, and intersections, oh my! Parallel lines and transversals are a present in the world around us. Learners begin by discovering the relationship of the angles formed by parallel lines and a transversal. They then apply...
Inside Mathematics
Rhombuses
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
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
Deductive and Inductive Reasoning
Students differentiate between inductive and deductive reasoning. In this geometry activity, students identify congruent figures and examine logos for congruency.
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.
Cord Online
Pyramids and Cones
Young mathematicians find the surface area and volume of a square pyramid and a cone. In what looks like a typical activity out of a textbook, you'll find an activity where learners find an unknown measurement of a pyramid or cone,...
Curated OER
Geometry Problem Set I
Students prove angles congruent by use of vertical angles definition, subtraction postulate, and transitivity postulate.
Curated OER
Crystals: Geometry and Groups
Learners discuss the importance of examining crystals and experiment growing them. In groups, they complete a project in which they use groups in geometry just like crystallographers. They practice solving the groups and proofs and...
Curated OER
Geometry: Angles
In this angle worksheet, students find the value for a given variable. They use similar figures, alternate interior angles, side angle side, and other geometric theorems and proofs to determine the value of the given variable. This...
Curated OER
Parallelograms
In this geometry activity, students identify properties of parallelograms. They use proof to justify their answers using quadrilaterals and parallelograms. there are 25 questions.
Curated OER
Points, Lines and Planes
For this points, lines and planes worksheet, 10th graders solve and complete 9 various types of problems. First, they name the planes that intersect a figure shown. Then, students determine the points that are collinear and coplanar in...
Curated OER
If-Then Statements and Postulates
In this if-then statements and postulates worksheet, 10th graders solve 6 different problems related to if-then statements and postulates in geometry. First, they identify the hypothesis and conclusion of each conditional statement and...
Curated OER
THE MEAN INDEX CARD
Students cut an index card to create three similar right triangles and explore the congruencies and proportions that exist. They investigate the properties of lines and concepts of congruency, similarity, tangency and symmetry of...
Virginia Department of Education
High School Mathematics Geometry Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...