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EngageNY
Using Unique Triangles to Solve Real-World and Mathematical Problems
How can congruent triangles help mark a soccer field? This is just one question your classes can answer after solving the real-world problems in the lesson. Each example posed through a word problem elicits higher-order thinking and...
EngageNY
Writing and Solving Linear Equations
Incorporate geometry into the solving linear equations lesson. Pupils use their knowledge of geometry to write linear equations which reinforces geometry measurement concepts while at the same time providing a familiar context for...
EngageNY
An Area Formula for Triangles
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....
Virginia Department of Education
Solve for the Unknown
How can shapes help solve literal equations? Scholars first learn to replace variables with shapes to aid in solving literal equations. A worksheet of practice problems helps hone the skill.
CK-12 Foundation
Pythagorean Theorem for Solving Right Triangles: Solving the Triangle
Observe the change in the trigonometric ratios as angles vary. An interactive provides the values of trigonometric ratios for both acute angles in a right triangle. Pupils create a right triangle to match given criteria and find the...
CK-12 Foundation
Lengths of Triangle Sides Using the Pythagorean Theorem: Find the Missing Side
What is the relationship between the sides of a right triangle? Learners use an interactive to create models of right triangles and view the relationship between the lengths of the sides. They finish by using the Pythagorean Theorem to...
Flipped Math
Parallelograms and Triangles
Expand area problems to incorporate prior knowledge. Pupils begin by reviewing the formulas for finding the area of parallelograms and triangles. The scholars apply previous learning of trigonometric ratios and the Pythagorean Theorem to...
Corbett Maths
Pythagoras Rectangles and Isosceles Triangles
When does the Pythagorean Theorem come in handy? An intriguing video uses the Pythagorean Theorem to solve problems other than simply finding the length of a side of a right triangle. Pupils find the diagonal of a rectangle and the...
CK-12 Foundation
Determination of Unknown Triangle Measures Given Area: Jib Sheets
Solving triangles is a breeze. Young boat enthusiasts solve problems involving triangles in the context of sails on a boat. They must apply different strategies, including the Law of Cosines and area formulas.
West Contra Costa Unified School District
Solving and Using Literal Equations
You literally need to use the resource. Young mathematicians solve geometric problems by using literal equations. They go on to solve distance/rate/time problems by using literal equations — a great progression that helps introduce the...
West Contra Costa Unified School District
Investigating Special Right Triangles
Scholars first investigate relationships in the side lengths of 30°-60°-90° triangles and 45°-45°-90° triangles. This knowledge then helps them solve problems later in the lesson plan about special right triangles.
Flipped Math
Unit 7 Review: Right Triangles
It is all right to spend some time with a review. After watching a short review video covering the materials from the unit, pupils work through 23 review problems. Scholars work on problems involving the Pythagorean Theorem and its...
Flipped Math
Special Right Triangles II
Show students that right triangles are radical. Learners see how the lengths of the sides of a 45-45-90 triangle relate. Using that relationship, pupils observe how to find any of the lengths given one side of a triangle. They go on to...
CCSS Math Activities
Smarter Balanced Sample Items: High School Math – Claim 2
Problem solve across the content standards. The presentation slides provide 19 sample items from the Smarter Balanced high school assessment. Items illustrate Claim 2, problem solving, of the test and are drawn from all the high school...
CK-12 Foundation
Angle-Angle-Side Triangles: Garden Gate
Good fences make good gardens. Individuals use an interactive to see how angles and sides relate in a triangular-shaped garden fence. They apply the Law of Sines to find the length of the garden gate (third side of triangle) given two...
Illustrative Mathematics
Bank Shot
Young geometers become pool sharks in this analysis of the angles and lengths of a trick shot. By using angles of incidence and reflection to develop similar triangles, learners plan the exact placement of balls to make the shot....
Digging Into Math
Classifying Triangles
Young mathematicians explore the world of three-sided shapes in this lesson plan on the different types of triangles. Starting with a general introduction to classification using Venn diagrams, children learn how to...
Illustrative Mathematics
Painting a Barn
When painting a barn you have to calculate surface area, and that is exactly what this resource is about. Not only will your future home owners calculate the surface area, but also the cost. It is a real-life problem that every that...
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...
Willow Tree
The Pythagorean Theorem
There isn't a more popular geometry formula than the Pythagorean Theorem! Learners understand the special side relationships in a right triangle. They use the Pythagorean Theorem to find missing sides and to solve problems. They begin...
Radford University
Right Triangle Sports
Who knew math could help with sports? An invigorating set of lessons encourages learners to apply right triangles in baseball, volleyball, hockey, football, and soccer. They use the Pythagorean Theorem, Pythagorean triples, special right...
EngageNY
Putting the Law of Cosines and the Law of Sines to Use
Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...
EngageNY
Modeling Using Similarity
How do you find the lengths of items that cannot be directly measured? The 13th installment in a series of 16 has pupils use the similarity content learned in an earlier resource to solve real-world problems. Class members determine...
EngageNY
Law of Sines
Prove the Law of Sines two ways. The ninth segment in a series of 16 introduces the Law of Sines to help the class find lengths of sides in oblique triangles. Pupils develop a proof of the Law of Sines by drawing an altitude and a second...