Curated OER
Exploring Polygons and The Greedy Triangle
Excellent lesson! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes), partners form the various shapes...
Curated OER
Tennis Triangle
Young scholars calculate the height of a tree or flagpole. They measure the shadow of the tree or flagpole and the length of a shadow of a meterstick. Using similar triangles, calculate the heigh. Devise two additional ways in which to...
EngageNY
Between-Figure and Within-Figure Ratios
Tie the unit together and see concepts click in your young mathematicians' minds. Scholars apply the properties of similar triangles to find heights of objects. They concentrate on the proportions built with known measures and solve to...
Illustrative Mathematics
Equal Area Triangles on the Same Base II
A deceptively simple question setup leads to a number of attack methods and a surprisingly sophisticated solution set in this open-ended problem. Young geometers of different strengths can go about defining the solutions graphically,...
EngageNY
Are All Parabolas Similar?
Congruence and similarity apply to functions as well as polygons. Learners examine the effects of transformations on the shape of parabolas. They determine the transformation(s) that produce similar and congruent functions.
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
Illustrative Mathematics
Coordinates of Equilateral Triangles
Can it be constructed? The task poses the question whether it is possible to have an equilateral triangle with its vertices located at integer coordinates. Pupils work with their knowledge of trigonometric ratios and the Pythagorean...
Curated OER
Similar Figures
In this geometry worksheet students explore similar polygons and determine measure of missing sides and angles. Students use indirect measurement with similar triangles and determine the area and volume of similar figures. The seven page...
Mathematics Assessment Project
Hopewell Geometry
Right triangles from 2,000 years ago? Learners investigate different right triangles found in the earthworks of the Hopewell people, a Native American culture that populated the United States from 200BC to AD 500. Learners apply concepts...
Curated OER
Countdown Challenge: Similarity
In this similarity worksheet, students use similar rectangles to find the length of a diagonal. They use symbols and write paragraphs to explain the problem. This one-page worksheet contains one similar problem with 13 related questions.
Curated OER
Mt. Whitney to Death Valley
This is an intriguing problem that brings together real-world data, technology, and mathematical problem solving. If visibility wasn't an issue, could you see from the highest point in the lower 48 states, Mt. Whitney, to the lowest...
Curated OER
Triangle Similarity
In this triangle similarity learning exercise, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles...
EngageNY
Similarity
Learn similarity through a transformations lens! Individuals examine the effects of transformations and analyze the properties of similarity, and conclude that any image that can be created through transformations is similar. The...
EngageNY
Congruence Criteria for Triangles—SAS
Looking for a different approach to triangle congruence criteria? Employ transformations to determine congruent triangles. Learners list the transformations required to map one triangle to the next. They learn to identify congruence if...
Curated OER
Geometric Applications
In this geometry worksheet, students solve 5 word problems. Each of the problems involves finding one side of a right triangle. Story problems relate the Pythagorean Theorem to building ramps, shadows, and the length of a banner.
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
Unit Squares and Triangles
This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle and angle...
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.
Curated OER
Mid-Segment of a Triangle
In this triangle worksheet, students examine triangle diagrams. They determine the perimeter, length of a line, midpoint of a line, and angle measurement from given information. This one-page worksheet contains ten problems.
Discovery Education
Exploring Geometry
Middle schoolers construct a three-dimensional model of a city using both similar and congruent figures and geometric transformations. City must have at least ten buildings with each building labeled and may be constructed out of paper...
Math Mammoth
Angles in a Triangle 2
Youngsters draw specified angles when given measurements of other angles and discover traits of angles in similar triangles. This one-page activity contains six multi-step problems.
Curated OER
Similarity
For this similarity worksheet, 10th graders solve and complete 14 different types of problems. First, they find the length of each segment given two lines parallel. Then, students find the measure of each segment of a parallelogram...
Curated OER
Similar Triangles on the Coordinate Plane
Pupils investigate triangles and their properties. In this geometry lesson, students differentiate between similar and congruent triangles. They use the SSS theorem to help identify the triangles that are similar or congruent.
National Council of Teachers of Mathematics
Bank Shot
Bank on geometry to line up the shot. The resource asks the class to determine the location to bank a cue ball in a game of billiards. Using their knowledge, class members determine where to hit the bumper to make a shot and discuss...