Curated OER
Algebra 2 & Trigonometry Practice: Law of Sines
In this law of sines worksheet, students solve 9 multiple choice and short answer problems. Students use the law of sines to missing side lengths and angles of triangles.
Curated OER
Missing Angle Measures
In this missing angle measures activity, students subtract the angle that is given from 180' to find the missing angle measure. Students complete 6 problems.
Curated OER
The Greedy Triangle-Intro to Geometric Shapes
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.
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.
EngageNY
Informal Proof of AA Criterion for Similarity
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
Curated OER
Hands-On: Sums of Angle Measures
In this angle measures instructional activity, students solve six word problems where they are given 6 different polygons, some of which are complex, and must determine angle measures in order to arrive at a solution.
Willow Tree
Common Geometric Figures
Geometry could be called the study of figures. An overview of the figures found in a typical geometry course contains a study of different triangles, quadrilaterals, and regular polygons.
EngageNY
Sine and Cosine of Complementary Angles and Special Angles
Building trigonometric basics here will last a mathematical lifetime. Learners expand on the previous lesson in a 36-part series by examining relationships between the sine and cosine of complementary angles. They also review the...
Illustrative Mathematics
Similar Triangles
Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...
University of Minnesota
Try Angle
Does practice make perfect or just improvement? Scholars practice drawing a triangle on an Etch-A-Sketch. They learn about the part of the brain that controls sensory-motor integration and apply that to an analysis question.
West Contra Costa Unified School District
Law of Sines
One must obey the sine laws. A instructional activity introduces and derives the Law of Sines for non-right triangles. With examples that use the Law of Sines to determine unknown measures in triangles, the instructional...
Arizona Department of Education
Area and Perimeter of Regular and Irregular Polygons
Extend young mathematicians' understanding of area with a geometry lesson on trapezoids. Building on their prior knowledge of rectangles and triangles, students learn how to calculate the area of trapezoids and other...
Curated OER
Geometry of Triangles Using a Protractor
Seventh graders use a protractor to measure angles and solve a problem involving distance. For this measuring angles with a protractor lesson plan, 7th graders calculate the distance of a line on a diagram by using a protractor to...
Curated OER
Tricky Triangle
In this triangle instructional activity, high schoolers solve 1 word problem about the lengths of a triangle. Students determine the length of the longest side given the ratio of the angle measures.
Curated OER
Triangles
For this triangles worksheet, 4th graders study the lengths that are stated for 3 triangles and describe each triangle by its sides. Students describe 3 additional triangles by their angles.
Curated OER
Special Right Triangles
In this special right triangle worksheet, students use the trigonometric functions to determine angle measurement or the length of one side of a right triangle. This one-page worksheet contains 18 problems. Answers are provided at the...
Illustrative Mathematics
Midpoints of the Sides of a Paralellogram
This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...
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
Exterior and Interior Angles of Triangles
Tenth graders explore the exterior and interior angles of triangles. They use a theorem in order to prove a theorem about all polygons. Students use the theorem and its applications to find the angles of different types of triangles.
Curated OER
Sum of Angles
In this sum of angles activity, 6th graders solve and complete 6 different types of problems. First, they identify different alternate and corresponding angles. Then, students state what the angles of a triangle add up to and how they...
Curated OER
Special Triangles and Circles
Students investigate special triangles and circles. In this geometry lesson, students construct a perpendicular bisector and discuss angles of a triangle. They find the angle bisectors, vetex and the types of circle constructed.
Curated OER
Triangles
Why are there so many different types of triangles? Be that as it may, beginning geometers need to understand the differences between equilateral, isosceles, scalene, and right triangles, and they get a visual approach with this...
Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
EngageNY
Unique Triangles—Two Sides and a Non-Included Angle
Construct an understanding of triangle congruence through a visual analysis. Young scholars find that given two sides and a non-included angle, sometimes two possible triangles are produced. Their analysis shows that if the non-included...