Curated OER
Triangle Side Lengths and Angles Measures
Learners identify missing sides and angles. In this geometry lesson, students use triangular theorems to identify the missing sides. They use the Pythagorean Theorem to find the different ratios of each side.
Curated OER
Angle-Side Relationships
Students calculate the different sides and angles of a triangle. For this geometry lesson, students use triangular properties to define the relationship between two triangle. They identify missing angles using the interior angle theorem.
EngageNY
Looking More Carefully at Parallel Lines
Can you prove it? Making assumptions in geometry is commonplace. This resource requires mathematicians to prove the parallel line postulate through constructions. Learners construct parallel lines with a 180-degree rotation and then...
EngageNY
The Angle-Angle (AA) Criterion for Two Triangles to Be Similar
What do you need to prove triangles are similar? Learners answer this question through a construction exploration. Once they establish the criteria, they use the congruence and proportionality properties of similar objects to find...
Utah Education Network (UEN)
Finding Missing Lengths of Similar Triangles
Middle and high schoolers explore the properties of similar triangles. In this geometry lesson, pupils play a similarity basketball game, sketch similar triangles, and find the missing measures of similar figures. They find the height of...
Curated OER
My Angle on Cooling
Students explore how the angle and distance of an object can change it's temperature. After reviewing how the position of the Earth affects the temperature of the planet, student groups design and perform an experiment to test how...
Willow Tree
Ratios and Proportions with Congruent and Similar Polygons
Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...
Hotchalk
Triangle Sum Theorem
Your visual geometry learners will appreciate triangle drawings as they model the triangle sum theorem and algebraically solve to find the missing interior angle in a triangle. Practice problems increase in complexity and vary in their...
Curated OER
Special Segments in a Triangle
For 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 segment. ...
Curated OER
Measuring Body Angles
Students use technology to graph and compare angles. In this geometry lesson, students range of motion in the environment. They identify the missing parts of polygons using similarity and congruence.
Utah Education Network (UEN)
It's All Just Similar to Me
Middle schoolers explore the concept of similar figures. For this similar figures lesson, pupils calculate scale factors of similar triangles. They find missing sides of triangles, and measure angles using protractors and measure sides...
Curated OER
Triangle Exterior Angles Theorem
Learners identify the measure of missing exterior angles. In this geometry lesson,students define and apply the exterior angle theorem to solve problems. They use Cabri software to create different angles and make investigations.
Curated OER
Angles in Triangles
Eighth graders translate word problems using mathematical ideas. In this geometry lesson, 8th graders identify angles of triangles using equations and the triangle sum theorem. They create angles with a protractor and straight edge.
EngageNY
The Definition of Sine, Cosine, and Tangent
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar triangles.
Curated OER
Area Measures and Right Triangles
Your class will investigate the relationship among different triangles. This geometry lesson plan, demonstrates how to make a connection between triangles and the Pythagorean Theorem. They identify the missing side or angle of a triangle.
Curated OER
Light Bounce
Learners solve problems involving triangles. In this geometry instructional activity, students apply properties of triangles to find the missing angles and sides. They identify angles of parallel lines cut by a transversal.
Curated OER
Trigonometric Ratios
Students measure and analyze angles. In this trigonometry instructional activity, students measure angles and distances use non-traditional techniques. They identify the different ratios of sine, cosine and tangent.
EngageNY
Using Trigonometry to Find Side Lengths of an Acute Triangle
Not all triangles are right! Pupils learn to tackle non-right triangles using the Law of Sines and Law of Cosines. After using the two laws, they then apply them to word problems.
Curated OER
How are Trig Ratios Used to Measure Triangle Sides
Young scholars identify the ratios of trig identities. In this geometry lesson, students solve the missing sides and angles of triangles using trig ratios. They relate the graphs and waves to real life scenarios.
Curated OER
Pythagorean Theorem
Students identify a right angle and right triangle. They perform WebQuests searching for similar figures and solve for the length of one of the sides given the other two.
Curated OER
Quadrilaterals
In this geometry worksheet, 10th graders solve problems with quadrilaterals. They calculate the sum of the angles, find missing angles and identify properties of quadrilaterals. There are 16 questions with an answer key.
Curated OER
The Law of Sines
Learners define the laws of sine as it relates to a right triangle. In this trigonometry lesson, students identify the properties of sine to help then find mixing sides of a right triangle. They also solve for the missing angles.
Curated OER
Law of Sines
In this Law of Sines worksheet, learners describe, in their own words, when to use the law of sines. They give an example of a problem using the law of sines. This two-page worksheet contains one problem and a sample answer.
Curated OER
Applying Special Right Triangles
For this geometry worksheet, 10th graders use the theorems regarding right triangles to find the missing length in a special right triangle. The one page worksheet contains eleven questions. Answers are included.