Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel lines cut...
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...
Curated OER
Special Angles on Parallel Lines
Tenth graders investigate parallel lines and their special angles cut by a transversal. In this geometry lesson, 10th graders identify and find corresponding, alternate interior, and alternate exterior angles formed when parallel lines...
Curated OER
Angles and Parallel Lines
Sixth graders draw parallel and intersecting lines to observe and examine the characteristics of alternate interior angles, vertical angles, corresponding angles, and supplementary angles. Through observation, they discover the...
Curated OER
Parallel Lines
For this geometry worksheet, 10th graders determine the measures of the angles formed when parallel lines are cut by a transversal. The two page worksheet contains eleven problems. Answers are not provided.
Curated OER
Skills and Application
In this geometry worksheet, students identify the different properties of parallel lines cut by a transversal. They identify the different angles created by such lines. There are 16 questions.
Curated OER
Parallel-o-Home
Students investigate the usage of parallel and perpendicular shapes in the real world. For this geometry lesson, students investigate shapes for properties that are related to the real world. They relate all the properties of shape tot...
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...
Curated OER
Geometry: Lesson 8
Eighth graders engage in a lesson that is concerned with the finding of angles that are found in different two dimensional figures. They compare and contrast exterior and interior angles while also determining the unknown measures of...
Curated OER
Challenge: Skills and Applications Lesson 3.4
In this geometry worksheet, students identify the missing angles formed by parallel lines and a transversal. They differentiate between parallel and perpendicular lines. There are four questions.
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
Hypatia: Angles
Introduce your young geometers to Hypatia, the first noted Greek female mathematician, and the properties of angles. Though this resource is missing worksheets that are needed to complete the lesson, the structure is sound and learning...
Curated OER
Sir Cumference and the First Round Table
In this circumference worksheet, students solve and complete 5 different figures illustrated on the sheet. First, they cut out each shape found on the bottom. Then, students use the shapes on the left as clues to create the corresponding...
Curated OER
Side Splitter Triangles
Students investigate the side splitter theorem. For this geometry lesson, students estimate and solve problems dealing with ratios and proportions. They identify angles created by lines that are parallel.
Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Education Development Center
Proof with Parallelogram Vertices
Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional students to frame their responses.
CCSS Math Activities
Smarter Balanced Sample Items: High School Math – Claim 3
Communication is the key. A presentation provides 25 sample items for Claim 3, Communicating Reasoning, for the Smarter Balanced High School Math assessment. Items require pupils to answer the question and provide logical reasoning to...
Ohio Department of Education
I Can Name that Angle in One Measure! - Grade Eight
Collaborative groups work with geometry manipulatives to investigate conjectures about angles. They create a graphic organizer to use in summarizing relationships among angles in intersecting, perpendicular and parallel lines cut by a...
Curated OER
Constructing Perpendicular Bisectors
Tenth graders investigate parallel lines and the angles formed when cut by a transversal. In this geometry lesson, 10th graders construct perpendicular lines and discuss midpoint, segments and perpendicular bisectors. They relate...
Curated OER
Constructing Midsegments of Triangles
Young scholars construct midsegments. In this geometry lesson, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.
EngageNY
Informal Proof of AA Criterion for Similarity
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
Curated OER
Corresponding Angles Worksheet
In this geometry worksheet, 10th graders find missing angles using parallel lines angle theorem with a transversal. There are 6 problems with an answer key to all 6 problems.
Math Worksheets Land
Co-Interior Angles Worksheet
Examine parallel lines with a transversal. From the given information, geometry fledglings find the angle measurement of interior angles. This two-page task contains six multi-step problems. Answers are provided on the last page.
Curated OER
Co-exterior Angles Worksheet
In this geometry worksheet, 10th graders analyze angles created by a transversal. They identify co-exterior angles as they review theorems dealing with parallel lines. There are 6 questions with an answer key.