Interactive
CK-12 Foundation

Reference Angles and Angles in the Unit Circle: Exploring Reference Angles

For Students 10th - 12th Standards
A steal of a deal — get four angles for the value of one. An interactive resource allows individuals to visualize all four angles that have the same reference angle. Pupils answer questions by using the interactive to create the...
Interactive
CK-12 Foundation

Square Roots and Irrational Numbers: Estimating Radicals

For Students 8th - 10th
Try out a resource using triangles to estimate radicals. An interactive app allows learners to approximate some irrational numbers involving square roots. They find the two consecutive numbers that an irrational number lies between...
Handout
Charleston School District

The Distance Between Points

For Students 8th - 10th Standards
Find the shortest distance from A to B using the Pythagorean Theorem! Scholars learn they can find the distance between two points by creating a right triangle using the horizontal and vertical lengths and applying the Pythagorean...
Interactive
CK-12 Foundation

Pythagorean Theorem to Determine Distance: Distance Between Friends

For Students 8th - 12th Standards
Pupils use an interactive to help visualize the right triangles needed to calculate distances between friends' houses. Individuals solve five problems on how to determine distances and comparing the distances.
Lesson Plan
Curated OER

Orthocenter Of a Triangle

For Teachers 8th - 10th
Students find the orthocenter of a triangle. In this geometry lesson plan, students identify where the altitudes meet in a triangle. They use Cabri software to explore acute, obtuse and right triangles.
Lesson Plan
Curated OER

Pythagorean Theorem: Triangles and Their Sides

For Teachers 8th - 10th
Students investigate triangles and their relationship to each other. For this geometry lesson, students solve right triangles using the properties of the Pythagorean Theorem. They differentiate between right, acute, straight and oblique...
Worksheet
Curated OER

Chapter 6: Geometry Perimeter and Area

For Students 10th - 12th
In this perimeter and area worksheet, students find the perimeter of various polygons.  They compute the perimeter, surface area, circumference, and volume of given figures.  Students explore trigonometric ratios.  This...
Lesson Plan
Curated OER

Pythagorean Theorem Spreadsheet

For Teachers 6th - 8th
Studetns use a spreadsheet to organize data on the sides of a triangle. They use the Pythagorean Theorem and the If then spreadsheet function to decide whether the three sides determine a right triangle. Learners work individual...
Worksheet
Mt. San Antonio Collage

Elementary Geometry

For Students 9th - 12th Standards
Your class may believe that geometry is a trial, but they don't know how right they are. A thorough math lesson combines the laws of logic with the laws of geometry. As high schoolers review the work of historical mathematicians and...
Lesson Plan
Curated OER

The Greedy Triangle-Intro to Geometric Shapes

For Teachers 4th - 6th Standards
 In this geometry lesson, learners read The Greedy Triangle and use geoboards to construct geometric shapes. They identify the number of sides and angles each shape has.
Worksheet
Curated OER

Angles Activities

For Students 5th - 8th
A series of geometry worksheets have mathematicians constructing, dissecting, overlapping, and measuring as they analyze angles in various contexts. Learners use symmetry and reflections in a compass rose to write instructions on...
Lesson Plan
Curated OER

Time Dilation and Geometry

For Teachers 9th - 10th
Learners solve problems of dilation and velocity. In this geometry lesson, students apply the Pythagorean Theorem to solve problems and relate it to time and velocity.
Interactive
CK-12 Foundation

Unit Circle: Medieval Castle Defense

For Students 10th - 12th Standards
Who needs a plan — let trigonometry protect you! Pupils determine the angle of an approaching enemy to a village wall. The scholars determine the exact value of trigonometric functions for the angle. Class members use trigonometry to...
Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Learners investigate the Pythagorean Theorem. In 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.
Worksheet
Curated OER

Pythagorean Theorem

For Students 8th - 9th
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...
Activity
Illustrative Mathematics

Slopes and Circles

For Teachers 9th - 12th Standards
An upper-level treatment of what is often presented as a basic concept (the right angle of an inscribed circle on the diameter), this activity really elevates the mathematical thought of the learner! Expected to develop formulas...
Worksheet
Math Mammoth

Triangles

For Students 6th - 8th Standards
A six-page packet walks, or bends learners through angles that combine to create triangles. Definitions are given for right triangles, obtuse and acute triangles. They draw angles according to directions, using a protractor to meet the...
Lesson Plan
Curated OER

Geometry Exploration Basic Trig Functions

For Teachers 10th
Tenth graders solve for missing sides on a triangle using the Pythagorean Theorem. In this geometry lesson, 10th graders are introduced to basic trigonometry functions as they solve problems of right triangles. They discuss the...
Lesson Plan
Curated OER

Special Segments in a Triangle

For Teachers 10th
In this geometry worksheet, 10th graders review the vocabulary associated with the special segments of a triangle and the associated points of concurrency and solve problems in which they find the indicated missing angle or...
Lesson Plan
Curated OER

Integration: Geometry - The Pythagorean Theorem

For Teachers 8th - 9th
In this math worksheet, students are given that c is the hypotenuse of a right triangle. Students must find 12 sets of missing measures. Students also use the Pythagorean Theorem to determine whether a given set of measures would form a...
Worksheet
Curated OER

The Triangle Midsegment Theorem

For Students 10th
For this geometry worksheet, 10th graders identify the vocabulary associated with the Triangle Midsegment Theorem and solve problems in which they find the size of a missing angle or segment.  The one page worksheet contains...
Lesson Plan
Curated OER

Medians and Altitudes of Triangles

For Teachers 10th
In this geometry worksheet, 10th graders determine if a given segment is a median or altitude of a triangle and use then find the indicated missing length or equation of a line.  The two page worksheet contains twenty...
Lesson Plan
Curated OER

Indirect Proof and Inequalities in One Triangle

For Teachers 10th
In this geometry worksheet, 10th graders order the sides and angles of a triangle and determine the range of the third side of a triangle given the lengths of two sides.  The one page worksheet contains sixteen questions. ...
Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 8th - 10th
Students use the inequality theorem to solve triangles and their properties. In this geometry lesson, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length needed to make a...