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,...
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...
El Paso Community College
Geometry Definitions
Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet.
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...
CK-12 Foundation
Special Triangle Ratios: Special Right Triangle Ratios
Go from one side length to any other side length with special right triangles. Individuals use the interactive to investigate the ratio of sides in 45-45 and 30-60 right triangles. Scholars make generalizations about the types of special...
CK-12 Foundation
Determination of Unknown Triangle Measures Given Area: Jib Sheets
Solving triangles is a breeze. Young boat enthusiasts solve problems involving triangles in the context of sails on a boat. They must apply different strategies, including the Law of Cosines and area formulas.
CK-12 Foundation
Right Triangles, Bearings, and Other Applications: Sailing Race
Help your class get their bearings when it comes to right triangles. Pupils determine distances traveled or components given the bearing of a sailboat using an interactive. The scholars develop a sense of finding the bearings of a given...
CK-12 Foundation
Distance Formula: Right Triangles
Go the distance with a far out resource. Individuals use an interactive to create right triangles on a coordinate plane to help find distance between two points. Challenge questions aid them in developing the distance formula.
CK-12 Foundation
Angle-Angle-Side Triangles: Garden Gate
Good fences make good gardens. Individuals use an interactive to see how angles and sides relate in a triangular-shaped garden fence. They apply the Law of Sines to find the length of the garden gate (third side of triangle) given two...
CK-12 Foundation
Possible Triangles with Side-Side-Angle
It's not often that math allows for multiple answers. Young mathematicians identify possible numbers of triangles when given two sides and a non-included angle. An interactive helps with this investigation.
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...
CK-12 Foundation
Trigonometric Functions and Angles of Rotation: The Triangle in the Circle
Go around the unit circle and create triangles. Pupils move a point around the unit circles to visualize the triangle associated with the angle in standard position. The three main trigonometric functions are defined in terms of the legs...
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.
CK-12 Foundation
Identifying Sets of Pythagorean Triples: Matching Problem
What sets of whole numbers make up the measures of side lengths in right triangles? Pupils use an interactive triangle to learn about Pythagorean triples. Individuals find missing values in triples and learn more about Pythagorean...