Curated OER
Review Geometry - Week 8 (Triangles)
In this triangle worksheet, students use similar figures to find the length of one side of two similar triangles. They find the area of a triangle inscribed in a rectangle. This two-page worksheet contains eight problems.
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Obtuse Triangles
Fourth graders explore obtuse triangles. In this geometry lesson, 4th graders make obtuse triangles with paper and scissors. They determine how to find the center of their triangle.
Curated OER
Perpendicular Bisector Theorem
High schoolers construct perpendicular bisectors using Cabri Jr. on their graphing calculator. They then construct conditional statements about perpendicular bisectors along with their converse, inverse, and contrapositive.
Curated OER
Proofs
In this geometric proof worksheet, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students use given...
Curated OER
Geometry Practice: Transformations, Isometries, and Tessellations
Five pages for geometry practice relating to symmetry provide mathematicians with exercises on transformations and symmetry, properties of isometries, compositions of transformations, tessellations with regular polygons, and other...
Curated OER
2-D polygons
A hands-on activity uses the Zome modeling system, and helps young geometers either learn or review their knowledge of polygons. Students build as many different 2-dimensional polygons as possible: triangle, square, rectangle, pentagon,...
EngageNY
Using Trigonometry to Determine Area
What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...
EngageNY
Similarity and the Angle Bisector Theorem
Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...
Inside Mathematics
Rugs
The class braids irrational numbers, Pythagoras, and perimeter together. The mini-assessment requires scholars to use irrational numbers and the Pythagorean Theorem to find perimeters of rugs. The rugs are rectangular, triangular,...
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...
Concord Consortium
Circling Trains
And round and round the park we go! Given a description of an amusement park with the locations of three attractions connected by walkways, learners consider what happens when additional attractions join the mix by doubling the length of...
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.
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Review of Triangles
Pupils investigate the Pythagorean Theorem. For this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
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Scalene Triangles
Fifth graders identify and classify scalene, equilateral, and isosceles triangles. In this triangle instructional activity, 5th graders define the different attributes of 3 types of triangles and sort them by descriptions and...
Curated OER
A Trying Triangle Problem
For this geometry worksheet, students calculate the length of the sides of a given triangle. They also find the perimeter and area of the triangles given its side values. There is an answer key with this problem.
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Triangle Classification
Students classify different types of triangles. In this geometry instructional activity, students identify and use properties of triangles. They differentiate between isosceles and equilateral triangles.
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Inscribed Angles
In this inscribed angles worksheet, 10th graders solve 13 various types of problems related to inscribed angles in geometry. First, they identify a circle illustrated and each arc of the circle. They, students find the measure of each...
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Geometry Straws
Students create different angles and shapes by using different lengths of straws. In this geometry straws lesson plan, students glue straws onto paper and define what they have made.
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Geometry Library
Fifth graders write and illustrate books to make a class library of math term books. They utilize vocabulary associated with geometry to make their books. For example, one character may be, Mr. A Cute.
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The Building Blocks of Geometry
Fifth graders explore geometric building blocks in the real world in order to describe the characteristics and relationships of points, lines, line segments, rays, and planes. This is the first lesson plan in a series of lessons in...
Curated OER
Construct, Bisect, Duplicate: Geometry Practice with Compass and Straight Edge
Geometers employ a straight edge and compass to duplicate and bisect segments and angles, construct perpendiculars, parallel lines, figures, and circles with points of concurrency. Ample practice with 65 questions across 8 worksheets. No...
Curated OER
Pythagorean Theorem
In this Pythagorean Theorem worksheet, students determine the length of a missing side of triangles. They read story problems, draw diagrams, and use the Pythagorean Theorem to solve real life problems. This one-page worksheet contains...
Curated OER
Proofs in Coordinate Geometry
In this coordinate geometry worksheet, students identify the lengths of a quadrilateral and find the slope of a line. They use proofs to identify the characteristics of given quadrilaterals. This one-page worksheet contains ten problems.
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Pre-Proof Warm-Ups
In this pre-proofs activity, 10th graders solve and complete 10 different problems that include various proofs and their definitions. They use the diagram shown and the given information to write the direct conclusion for each case....