Curated OER
Triangles in Architecture
Students find triangles in the real world. In this geometry instructional activity, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
Curated OER
Parts of Similar Triangles
In this parts of similar triangles worksheet, 10th graders solve 6 different problems related to determining the value of various parts of similar triangles. First, they find the value of x in the 2 figures shown. Then, students find the...
Curated OER
Special Right Triangles
Young scholars identify the different parts of a right triangle. In this geometry lesson, students use the Pythagorean Theorem to identify missing sides and angles of a right triangle. They work with irrational and rational roots.
Math Mammoth
Angles in a Triangle 2
Youngsters draw specified angles when given measurements of other angles and discover traits of angles in similar triangles. This one-page instructional activity contains six multi-step problems.
Houghton Mifflin Harcourt
Introducing the Concept: Triangles and Quadrilaterals
Guide your geometers through the process of constructing polygons. They learn how to draw triangles, squares, parallelograms, rectangles, rhombuses, and trapezoids with specified angles using a protractor and a ruler. The lesson plan...
Curated OER
Polygons
Students investigate the concepts related to the study of polygons. They specifically look at how angles is related. The lesson includes specific examples and dialogue to be used by the teacher during direct instruction and independent...
Curated OER
Discover the Pythagorean Theorem
Students explore the Pythagoras theorem. In this geometry lesson, students make right triangles and identify the parts of the triangle. Students complete measurements of the sides of the triangle.
Curated OER
Proofs
In this geometric proof instructional activity, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students...
Curated OER
Archimedes
In this Archimedes worksheet, students complete and respond to 4 different problems related to different triangles. First, they find the midpoint of each side of a given triangle. Then, students connect the midpoints with the opposite...
EngageNY
Solving Problems Using Sine and Cosine
Concepts are only valuable if they are applicable. An informative resource uses concepts developed in lessons 26 and 27 in a 36-part series. Scholars write equations and solve for missing side lengths for given right triangles....
Flipped Math
Unit Circle and Radians
Measure angles is easy as pi. Pupils review special right triangles to find exact values for trigonometric functions. Scholars learn about radians and how they connect to measurements in degrees. They find exact and approximate values of...
West Contra Costa Unified School District
Law of Sines
One must obey the sine laws. A lesson 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 lesson checks to see if the Law...
CK-12 Foundation
Basic Inverse Trigonometric Functions: Ladder
Lean a ladder against the wall to create an angle. Class members use an interactive application to determine the angle a ladder makes with the ground. Individuals respond to five questions using inverse trigonometric functions.
Mathed Up!
Loci and Constructions
A General Certificate of Secondary Education math review has class members make basic constructions. Using a protractor and a ruler along with a compass, pupils develop drawings of triangles with given measurements. Scholars use their...
Corbett Maths
Hexagon Inscribed Within a Circle
Mark off the length of the radius around the circle. Using a compass, the presenter shows how to construct a regular hexagon in a circle. Pupils see how triangles formed in the hexagon are equilateral, allowing for the construction to...
Scholastic
Study Jams! Congruent Figures
There is more to congruency than just looking similar. Learn the difference and calculate the matching angles and sides to prove the congruence between figures. Lesson has step-by-step slides and follows with an assessment.
Concord Consortium
In Oz We Tryst
The shortest distance from point A to point B is a straight line, but measuring distance gets more complicated when there are three points! Given the location of three friends, individuals determine the best point for all three friends...
Curated OER
How are Trig Ratios Used to Measure Triangle Sides
Pupils identify the ratios of trig identities. In this geometry lesson plan, students solve the missing sides and angles of triangles using trig ratios. They relate the graphs and waves to real life scenarios.
Curated OER
Finding the Angle Measurements in Isosceles Triangles
In this angles worksheet, 9th graders find the angle measurements in four isosceles triangles. Two of these triangles are drawn inside a circle, where two of the sides of the triangles are formed by radii.
Curated OER
Chapter 4 - Objective 3.1 - Perimeter & Angle Measure
For this perimeter and angle measure worksheet, students find the length of the side of triangles and rectangles from given information. They read story problems, write equations and solve the problem. This one-page worksheet contains...
Curated OER
Geometry and Triangles
In this geometry triangles instructional activity, students first determine how many degrees are found in one half and in three-fifths a revolution. Then they find the supplement of the two angles given and the radius of a circle....
Curated OER
Identify Similar Triangles With Proofs
In this similar triangle worksheet, students write a two-column proof to explain why determined triangles are similar. Given some line lengths and angle measurements, students use proofs to identify the ratio of specified angles. This...
Houghton Mifflin Harcourt
Developing the Concept: Triangles and Quadrilaterals
Exact narrative and examples make this lesson on polygons easy to implement. Through it, your class will learn how to use a protractor and ruler to construct triangles and quadrilaterals according to your directions. Your class will be...
Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this...