Curated OER
Arcs in Circles
In this arcs in circles activity, 10th graders identify 10 different circles and the measurement of their arcs. First, they determine the length of a minor arc to the nearest integer. Then, students determine the radius of a circle...
Curated OER
Inscribed Quadrilaterals and Parallelograms
Students differentiate between inscribed quadrilaterals and parallelograms. In this geometry lesson, students identify the shaped of the polygons when it is inscribed inside of a circle. They calculate the missing angles of the inscribed...
Curated OER
Exploring Geometric Mean
Students solve problems using geometric means. In this geometry lesson plan, 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. In 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
Quadrilaterals
In this quadrilaterals worksheet, 10th graders solve 10 different problems that include the quadrilateral family and properties. First, they determine the area of a rectangle given the perimeter and length. Then, students determine the...
Curated OER
Concurrent Lines in Triangles
Learners 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. Learners use a...
Curated OER
Why can't We Use SSA to Prove Triangles Congruent?
Students investigate triangles and congruences. In this geometry instructional activity, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
Curated OER
Triangles with Collinear Circumcenters
Learners identify the circumcenter of a triangle. In this geometry lesson, students construct a perpendicular bisector using a straight edge and a compass. They differentiate between triangles and collinear points.
Curated OER
Composition of Reflections
Young scholars perform reflections and translations of polygons. In this geometry instructional activity, students perform reflection in two parallel lines. They use Cabri to observe the transformation and rotations of each shape.
Curated OER
Inscribed Right Triangles
Learners calculate the measurements of the inscribed angles of a triangle. For this geometry lesson, students relate the hypotenuse of a right triangle and the diameter of a circle to each other. They calculate the diameter of a circle...
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that involve various congruent triangles. First, they determine the length of the third side given the other two. Then, students determine the...
Curated OER
Dividing Line Segments into n Congruent Parts
Students identify lines, and line segments. In this geometry lesson plan, students divide line segments into equal congruent parts. They complete a laboratory activity dealing with lines and segments.
Curated OER
Angles, Parallel Lines, and Polygons
Young scholars examine how to investigate polygons using an instrument of their own construction. They should be able to prove the general formula for the number of degrees in any polygon (including a triangle). Finally they investigate...
Curated OER
Congruent Triangles - Is This Enough Information?
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
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...
K12 Reader
Geometric Shape Names
Combine math and language arts in the same lesson with a reading passage about number prefixes in geometric shapes. After reading several short paragraphs about the different prefixes used in shape names, kids answer five comprehension...
EngageNY
Rotations of 180 Degrees
What happens when rotating an image 180 degrees? The sixth lesson in the series of 18 takes a look at this question. Learners discover the pattern associated with 180-degree rotations. They then use transparency paper to perform the...
Teach Engineering
Stay in Shape
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
Cornell University
Resolution—Not Just for the New Year
Experiment with optical resolution using an inquiry-based lesson. Young researchers calculate fellow classmates' optical resolutions. They apply the information to understand the inner workings of optical instruments.
Curated OER
Making Parallel Lines
Students differentiate between parallel and perpendicular lines. For this geometry lesson, students make conjectures and apply it to solve real life situations. They collect data and make predictions based on the data.
Curated OER
Solving Intercepted Arcs
Students investigate circles and its arcs. In this geometry activity, students identify the relationship between an circle and its intercepted arcs. THey identify the central and inscribed angles.
Curated OER
Obtuse Triangles
Fourth graders explore obtuse triangles. In this geometry activity, 4th graders make obtuse triangles with paper and scissors. They determine how to find the center of their triangle.
Curated OER
Regular Polygons
Fifth graders explore polygons. In this math lesson, 5th graders find examples of regular polygons in the classroom and measure the sides of figures to determine if they are regular polygons.
Curated OER
Drawing Quadrilaterals
In this math instructional activity, learners draw quadrilaterals and also find the sums of the inner angles for each. They practice drawing rhombuses as unique quadrilaterals.