Lesson Plan
Curated OER

Circumscribed Polygons

For Teachers 9th - 10th
Students investigate polygons and construct ferris wheels. In this geometry lesson plan, students create a circle and differentiate properties of circles and polygons. They compare the relationship between angles and circumscribed polygons.
Worksheet
Curated OER

Concurrent Lines, Medians and Altitudes

For Students 9th - 10th
For this geometry worksheet, students construct angles and identify medians and altitudes. They use a compass and protractor to perform heir construction. There are 28 questions.
Worksheet
Curated OER

Triangles

For Students 10th
In this triangles worksheet, 10th graders solve 10 different problems that include determining the measurement of various angles. First, they determine the area of a triangle illustrated on the sheet. Then, students use the picture to...
Lesson Plan
Curated OER

Side Splitter Triangles

For Teachers 8th - 11th
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.
Lesson Plan
Curated OER

Exploring the Properties of Rectangular Prisms.

For Teachers 9th - 10th
Students define properties of rectangular prisms. In this geometry lesson, students identify the relationship between two and three dimensional objects. They use Cabri technology to graph their figures.
Lesson Plan
Curated OER

Exploring Properties of Rectangular Prisms

For Teachers 8th - 10th
Learners explore the properties of rectangular prisms. In this geometry lesson, students identify properties of two and three dimensional shapes. They use Cabri technology to create polygons and solve problems.
Worksheet
Curated OER

Quiz: Triangle Inequality Theorem

For Students 7th - 8th
In this triangle inequality theorem worksheet, students determine the lengths of the sides of triangles and identify the measure of angles. This one-page worksheet contains ten triangle theorem problems.
Worksheet
Curated OER

Area of Sector and Segment

For Students 10th
In this area of sector and segment worksheet, 10th graders solve and determine the area of 10 different illustrations. First, they determine the area of a shaded sector given the measurements. Then, students determine the area of each...
Worksheet
Curated OER

Arcs in Circles

For Students 10th
In this arcs in circles worksheet, 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...
Lesson Plan
Curated OER

Inscribed Quadrilaterals and Parallelograms

For Teachers 9th - 10th Standards
Students differentiate between inscribed quadrilaterals and parallelograms. For 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...
Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
Students solve problems using geometric means. In this geometry instructional activity, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
Lesson Plan
Curated OER

Exploring Geometric Mean

For Teachers 8th - 10th
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...
Worksheet
Curated OER

Quadrilaterals

For Students 10th
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...
Lesson Plan
Curated OER

Concurrent Lines in Triangles

For Teachers 9th - 12th
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...
Lesson Plan
Curated OER

Why can't We Use SSA to Prove Triangles Congruent?

For Teachers 9th - 10th
Students investigate triangles and congruences. In this geometry lesson, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.
Lesson Plan
Curated OER

Triangles with Collinear Circumcenters

For Teachers 9th - 10th
Students 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.
Lesson Plan
Curated OER

Composition of Reflections

For Teachers 9th - 10th
Students perform reflections and translations of polygons. In this geometry lesson, students perform reflection in two parallel lines. They use Cabri to observe the transformation and rotations of each shape.
Lesson Plan
Curated OER

Inscribed Right Triangles

For Teachers 7th - 9th
Students calculate the measurements of the inscribed angles of a triangle. In this geometry activity, students relate the hypotenuse of a right triangle and the diameter of a circle to each other. They calculate the diameter of a circle...
Worksheet
Curated OER

Congruent Triangles

For Students 10th
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...
Lesson Plan
Curated OER

Dividing Line Segments into n Congruent Parts

For Teachers 9th - 10th
Learners identify lines, and line segments. In this geometry lesson, students divide line segments into equal congruent parts. They complete a laboratory activity dealing with lines and segments.
Lesson Plan
Curated OER

Angles, Parallel Lines, and Polygons

For Teachers 5th - 6th
Students 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 an...
Lesson Plan
Curated OER

Congruent Triangles - Is This Enough Information?

For Teachers 7th
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
Lesson Plan
EngageNY

Informal Proof of AA Criterion for Similarity

For Teachers 8th Standards
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...
Lesson Plan
EngageNY

Rotations of 180 Degrees

For Students 8th Standards
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...