EngageNY
Dividing Segments Proportionately
Fractions, ratios, and proportions: what do they have to do with segments? Scholars discover the midpoint formula through coordinate geometry. Next, they expand on the formula to apply it to dividing the segment into different...
Curated OER
Triangles
In this triangles worksheet, 10th graders solve and complete 6 various types of problems. First, they draw a median and the altitude from the given angle in each triangle illustrated. Then, students determine which angle is equidistant...
Curated OER
Corresponding Sides and Angles of Similar Triangles
Students differentiate between corresponding sides ad angles of two triangles. In this geometry lesson, students identify the differences as well as the similarities between two triangles. They differentiate between similar and...
Curated OER
Congruent Triangles
Tenth graders explore congruent triangles. For this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles are congruent by SSS, ASA, AAS, or SAS.
Curated OER
Triangle Side Lengths and Angles Measures
Students identify missing sides and angles. In this geometry lesson, students use triangular theorems to identify the missing sides. They use the Pythagorean Theorem to find the different ratios of each side.
Curated OER
Unit Circle and Triangle
Students apply the Unit Circle to solve ratios of triangles. For this geometry lesson, students derive the different ratios of a triangle using the Pythagorean Theorem. They find the angles of a unit circle using a right triangle.
Curated OER
Right Trianlges: Missing lenght
In this geometry worksheet, 10th graders use the Pythagorean Theorem to find the indicated missing side of a right triangle. The one page worksheet contains one problem. Answers are not provided.
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...
Curated OER
Tilted Squares and Right Triangles
Students investigate squares. They generate patterns from structured situations and find a rule for the general term and express it using words and symbols. Students generate patterns from a rule and substitute values and formulas.
Curated OER
Identify Angles: Obtuse, Right, Straight and Acute
In this triangle worksheet, students identify angles as either obtuse, right, straight or acute. A reference web site is given for additional activities.
Curated OER
Unit Circle Triangle
Students find the different ratios of a right triangle. In this geometry lesson, students apply the concept of the Pythagorean theorem as they identify the different angles and parts of a Unit Circle. They find the ratios of sine,...
Curated OER
Relationship between Exterior and Remote Interior Angles in a Triangle
In this triangle worksheet set, 9th graders find the relationship between the exterior and remote interior angles in triangles. They determine the formula, and apply it in 15 problems. They use a compass as needed to measure angles.
Curated OER
Basic Shapes
Students create books about shapes. In this shape lesson plan, students select a topic such as points, lines, angles, planes, polygons, quadrilaterals, triangles, circles, and polyhedra. In groups, they create an illustrated...
Curated OER
Geometry and Measurement
Students view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Students use pegboards and string to create more...
Curated OER
Triangles Introduction
Students explore geometry by drawing various shapes in class. In this triangle characteristics lesson, students identify the attributes that classify a shape as a triangle and practice using their bodies to create triangles in class....
Curated OER
The Right Angle
For this geometry worksheet, 10th graders determine the answer to a vocabulary questions and then follow the give rules to place the answer in the appropriate place on the crossword grid. The one page worksheet contains 18...
Curated OER
Using Slope Angles
In this geometry learning exercise, 10th graders use right triangle trigonometry to solve problems involving angle of elevation or depression. The one page learning exercise contains eleven problems. Answers are not provided.
Noyce Foundation
Parallelogram
Parallelograms are pairs of triangles all the way around. Pupils measure to determine the area and perimeter of a parallelogram. They then find the area of the tirangles formed by drawing a diagonal of the parallelogram and compare their...
EngageNY
Geometry Module 5: Mid-Module Assessment
How can you formally assess understanding of circle concepts? Pupils take a mid-module assessment containing five questions, each with multiple parts.
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...
EngageNY
Thales’ Theorem
Isn't paper pushing supposed to be boring? Learners attempt a paper-pushing puzzle to develop ideas about angles inscribed on a diameter of a circle. Learners then formalize Thales' theorem and use geometric properties to develop a proof...
Curated OER
Inscribing a Square in a Circle
Inscribing a square in a circle brings up a number of interesting geometry topics including triangle congruence and how to prove a quadrilateral is a square. This activity is followed up by finding the area of the square and determining...
Curated OER
Where's That Shape?
Your kindergartners know their shapes - but can they identify their locations? A 3x3 grid contains geometric shapes such as diamonds, circles, and hexagons, and pupils locate the shapes within the grid. Which shape is underneath the...
West Contra Costa Unified School District
Law of Sines
Laws are meant to be broken, right? Learners derive the Law of Sines by dropping a perpendicular from one vertex to its opposite side. Using the Law of Sines, mathematicians solve for various parts of triangles.