Curated OER
Art or Junk? Discovering the Triangle Inequality
Middle schoolers study the triangle inequality. They will identify, compare, and analyze attributes of two and three-dimensional shapes. Then they develop vocabulary to describe the attributes. They also use manipulatives to analyze the...
Curated OER
Lengths of Horizontal and Vertical Line Segments
Use this lengths of horizontal and vertical line segments practice worksheet to have learners sharpen their problem solving skills as they solve six story problems.
Curated OER
Investigating Trigonometric Ratios Through Similar Right Triangles
Students identify similar and congruent right triangles. In this geometry lesson, students use trigonometric ratios to identify missing sides and angles of a triangle. They differentiate similar and congruent triangles.
EngageNY
Checking for Identical Triangles II
Given a diagram of connected or overlapping triangles, individuals must find congruent parts using various properties. Pictures include reflexive sides and vertical angles amongst the marked congruent parts.
Mathed Up!
Rotation
Two videos show first how to perform a rotation, given the center, the angle, and the direction of rotations. Individuals then see how to find what the rotation is from one figure to another. Pupils practice doing both in seven problems...
EngageNY
Prove the Pythagorean Theorem Using Similarity
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.
Mathematics Vision Project
Module 4: Similarity and Right Triangle Trigonometry
Right you are to use a great resource. Starting with a lesson on dilations, scholars learn about similarity transformations and similar triangles. They use the knowledge to develop an understanding of right triangle trigonometry in later...
Radford University
Parallel Lines Cut by a Transversal
Use the parallel lines to find your way. After first reviewing geometric constructions and the relationships between angles formed by parallel lines and a transversal, young mathematicians write proofs for theorems relating to parallel...
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...
Concord Consortium
Mirror, Mirror I
How do you see yourself? Young mathematicians consider whether it's possible to view their whole bodies in a mirror with a length that is half their height. They write a letter to a friend explaining their positions mathematically.
K12 Reader
The Art of M.C. Escher
Show your class one way in which art and math are related by teaching them about M.C. Escher. Class members read a brief passage and then respond to five related questions.
Curated OER
Triangle Fundamentals
In this geometry worksheet, students observe a triangle marked with three angles and are given two measures to find the missing third measure. A second diagram is given with six angles. There are 20 questions.
Curated OER
Right Triangle Trigonometry: Finding Missing Sides and Angles
In this right triangle trigonometry worksheet, students find the measure of specified angles. Students determine the length of the missing side of a right triangle. This four-page worksheet contains 24 problems. Answers to the worksheet...
Curated OER
Kuta Software - Infinite Geometry: Similar Triangles
In this similar triangles instructional activity, students solve 20 short answer problems. Students determine if two given triangles are similar. Students determine the type of similarity given two triangles. Students are given a...
Curated OER
Chapter 7 Final Review Extra Problems
In this Geometry review worksheet, learners describe the relationships of two common triangles. They find the area of a segment created by a given sector of a circle for two circles. Students find the length of an arc bounded by the...
Curated OER
Law of Sines
In this Law of sines worksheet, 10th graders solve 10 different sets of problems related to the Law of Sine and Ambiguous case. First, they determine the ratio of the sides of the triangle with the given measurements. Then, students...
Curated OER
Cabri Jr. Perpendicular Bisector of a Chord
Your learners will construct the perpendicular bisector of a chord. They use Cabri Jr. to construct a circle and a perpendicular bisector of a chord. They then measure lengths of the chords and perpendicular bisectors. Learners use...
Curated OER
Triangle Puzzler
Students are introduced to some basic concepts of geometry. They explain that the definition of a triangle is a figure with three sides, three angles, and three points. Triangles can be named by using three points in their correct sequence.
Curated OER
Types of Triangles
Students classify triangles by the length of their sides. In this geometry lesson plan, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
Curated OER
Isosceles Triangles
Students identify the properties of an isosceles triangle. In this geometry lesson plan, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
Curated OER
Properties of Triangles
Learners explore the relationship between how big a side of a triangle is and how big its opposite angle is by creating triangles using an interactive website.
Curated OER
Sum of Interior/Exterior Angles with Wilbur
Students identify the interior and exterior measures of polygons. In this geometry lesson, students identify the formula for interior angles of polygons. They differentiate between triangular and polygons angles.
Curated OER
Acute Triangles
Learners study acute triangles. They measure angles using a protractor, then classify the triangles as either right, obtuse, or acute. Everyone creates a design for a Navajo rug using only acute triangles.
Curated OER
Triangles Inscribed in a Circle
Are you tired of answers without understanding? Learners can give a correct response, but do they really understand the concept? Have young mathematicians think deeper about linear functions, angles, and formulas in algebra....