Illustrative Mathematics
Illustrative Mathematics: G Srt Shortest Line Segment From a Point P to a Line L
In this task, young scholars develop an understanding that the shortest path from a point to a line always meets the line at a right angle. Aligns with G-SRT.C.8.
Illustrative Mathematics
Illustrative Mathematics: G Srt, G Mg How Far Is the Horizon?
Some friends are at the beach looking out onto the ocean on a clear day and they wonder how far away the horizon is. A second problem asks how far the horizon would be from the top of a mountain. Students must also answer a question...
Illustrative Mathematics
Illustrative Mathematics: 4.g Are These Right?
The purpose of this task is for students to measure angles and decide whether the triangles are right or not. Aligns with 4.G.A.2.
Illustrative Mathematics
Illustrative Mathematics: 8.g Pythagorean Theorem in Mathematical Context
Eighth graders are shown a drawing of a rectangle with a central triangle bordered by three right triangles. They are asked to prove whether or not the middle triangle is also a right triangle. Aligns with 8.G.B.
Khan Academy
Khan Academy: Trigonometric Ratios in Right Triangles
Given the side lengths of a right triangle, find the sine, cosine, or tangent of one of the acute angles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Illustrative Mathematics
Illustrative Mathematics: G Srt Defining Trigonometric Ratios
The purpose of this task is to use the notion of similarity to define the sine and cosine of an acute angle. Aligns with G-SRT.C.6.
Khan Academy
Khan Academy: Pythagorean Theorem Challenge
In this exercise, students practice using the Pythagorean Theorem in word problems. Students receive immediate feedback and have the opportunity to watch a video, get hints, or try questions repeatedly.
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
Analyze Math
Analyze Math: Free Math Tutorials: Triangles
The geometry tutorial investigates the definitions and properties of triangles. Topics included are isosceles, equilateral, and right triangles. In addition, the sine and cosine laws of triangles are defined.
CK-12 Foundation
Ck 12: Converse of the Pythagorean Theorem
[Free Registration/Login may be required to access all resource tools.] Learn about the converse of the Pythagorean Theorem and some of its applications. Also explains how to identify acute and obutse triangles through the use of the...
CK-12 Foundation
Ck 12: Right Triangles, Bearings, and Other Applications
[Free Registration/Login may be required to access all resource tools.] Find distances using angles expressed as bearings. Here you'll learn how to relate right triangle relationships to course bearings.
CK-12 Foundation
Ck 12: Geometry: Pythagorean Theorem and Pythagorean Triples
[Free Registration/Login may be required to access all resource tools.] Apply the Pythagorean Theorem and its converse. Includes videos, exercises, links to interactive activities, etc.
Purple Math
Purplemath: Special Angle Values: 30 60 90 and 45 45 90 Triangles
Explains a simple pictorial way to remember basic reference angle values. Provides other memory aids for the values of trigonometric ratios for these "special" angle values, based on 30-60-90 triangles and 45-45-90 triangles.
Exploratorium
Exploratorium: Ilion High: Build a Clinometer
Instructions for building a clinometer are given on this page. Clinometers can be used to measure the angle of elevation of a right triangle, and in turn find the height of large objects.
BBC
Bbc: Bitesize: Maths: 2 D Shapes
Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.
CK-12 Foundation
Ck 12: Geometry: Triangle Area Grades 6 7
[Free Registration/Login may be required to access all resource tools.] Find the areas of triangles given their base and height dimensions.
CK-12 Foundation
Ck 12: Trigonometry: Angles of Elevation and Depression
[Free Registration/Login may be required to access all resource tools.] Find distance using right triangles and angles of elevation or depression.
Khan Academy
Khan Academy: Solve for a Side in Right Triangles
Given one side length and an acute angle in a right triangle, find another side using trigonometry. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Alabama Learning Exchange
Alex: Have Your Math and Eat It, Too!
For this two-day lesson, students will collaborate to create a healthy pizza using only geometric items that have been precisely measured. Students must identify the items as triangle, quadrilateral (parallelogram), or cube. Next,...
Alabama Learning Exchange
Alex: Card Table Project
Students will work in groups to design a card table. Students will communicate with each other through a class blog or class discussion page. Students will then work in groups to design a card table. After the design phase, students will...
Alabama Learning Exchange
Alex: Geometric Mean and Indirect Measurement
In this inquiry-based instructional activity, learners will work in groups to gather measurements needed to approximate the height of a building. Students will discover how geometric mean can be used to find the lengths of missing sides...
Math Open Reference
Math Open Reference: Sine (Sin) Function Trigonometry
A complete reference guide to the sine function. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Khan Academy
Khan Academy: Solve for a Side in Right Triangles
Given one side length and an acute angle in a right triangle, find another side using trigonometry.
Geometry Help
Geometry Help: Right Triangles
Explains the basic concept of right triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.