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110 resources with the concept geometric proofs

Lesson Planet

Connecting Algebra and Geometry

For Teachers 9th - 10th Standards
Connect algebra and geometry on the coordinate plane. The eighth unit in a nine-part integrated course has pupils develop the distance formula from the Pythagorean Theorem. Scholars prove geometric theorems using coordinates including...
Lesson Planet

Congruence, Construction and Proof

For Teachers 9th - 10th Standards
Learn about constructing figures, proofs, and transformations. The seventh unit in a course of nine makes the connections between geometric constructions, congruence, and proofs. Scholars learn to construct special quadrilaterals,...
Lesson Planet

Pythagorean Theorem

For Students 8th Standards
Investigate the meaning of the Pythagorean Theorem through modeling. After comparing the area of the square of each side, individuals cut triangles and squares to facilitate the comparison.
Lesson Planet

Congruent Triangles

For Teachers 9th - 11th Standards
Is this enough to show the two triangles are congruent? Small groups work through different combinations of constructing triangles from congruent parts to determine which combinations create only congruent triangles. Participants use the...
1 In 1 Collection
EngageNY

Pythagorean Theorem, Revisited

For Students 8th Standards
Transform your pupils into mathematicians as they learn to prove the popular Pythagorean Theorem. The 16th lesson in the series of 25 continues by teaching learners how to develop a proof. It shows how to prove the Pythagorean Theorem...
1 In 1 Collection
EngageNY

End-of-Module Assessment Task: Grade 8 Mathematics (Module 7)

For Students 8th Standards
It's time to discover what your classes have learned! The final lesson in the 25-part module is an assessment that covers the Pythagorean Theorem. Application of the theorem includes distance between points, the volume of...
1 In 1 Collection
EngageNY

Converse of the Pythagorean Theorem

For Students 8th Standards
Discover a new application of the Pythagorean Theorem. Learners prove and apply the converse of the Pythagorean Theorem in the 17th lesson in a 25-part series. The examples ask learners to verify right triangles using the converse of the...
1 In 1 Collection
EngageNY

Informal Proof of AA Criterion for Similarity

For Teachers 8th Standards
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...
1 In 1 Collection
EngageNY

Informal Proof of the Pythagorean Theorem

For Students 8th Standards
Prove the Pythagorean Theorem using multiple informal proofs. Scholars first develop an understanding of the origins of the Pythagorean Theorem through proofs. They round out the lesson by using the theorem to find missing side lengths...
1 In 1 Collection
EngageNY

Angle Sum of a Triangle

For Students 8th Standards
Prove the Angle Sum Theorem of a triangle using parallel line and transversal angle relationships. Pupils create a triangle from parallel lines and transversals. They find angle measures to show that the angles of a triangle must total...
1 In 1 Collection
EngageNY

Informal Proofs of Properties of Dilations

For Teachers 8th Standards
Challenge the class to prove that the dilation properties always hold. The lesson develops an informal proof of the properties of dilations through a discussion. Two of the proofs are verified with each class member performing the...
Lesson Planet

Rhombuses

For Teachers 9th - 12th Standards
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
Lesson Planet

Quadrilaterals

For Teachers 9th - 12th Standards
What figure is formed by connecting the midpoints of the sides of a quadrilateral? The geometry assessment task has class members work through the process of determining the figure inscribed in a quadrilateral. Pupils use geometric...
Lesson Planet

Square

For Students 8th - 12th Standards
Don't be a square! Young mathematicians determine the slope and length of a line segment. They then prove whether four given coordinate points form a square.
3:58
Lesson Planet

Triangle Angle Sum

For Students 9th - 12th Standards
Don't believe everything that you hear — make them prove it! The video shows two methods to prove the Triangle Angle Sum Theorem. The following two videos apply the theorem to finding missing angle measures.
Lesson Planet

Coordinate Proofs

For Students 8th - 11th Standards
How do you know you know? Prove it! The guide goes through several examples and includes a link to a video to teach learners how to work through coordinate proofs. The goal is to prove that different shapes are indeed that shape. 
Lesson Planet

Congruent Triangles Applications

For Students 9th - 12th Standards
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the worksheet provides a brief introduction of the different properties and postulates. The remaining pages contain...
7:37
Lesson Planet

Pythagorean Theorem Proofs

For Students 10th - 12th Standards
Your class knows the Pythagorean Theorem, but can they prove it? A series of three videos shows two proofs of the Pythagorean Theorem and use it to classify triangles. 
Lesson Planet

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 the...
Lesson Planet

Isosceles Triangles and Special Line Segments

For Students 9th - 12th Standards
Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...
Lesson Planet

Pythagorean Theorem and Converse

For Students 8th Standards
You've heard that it is true, but can you prove it? Scholars learn the Pythagorean Theorem through proof. After an overview of proofs of the theorem, learners apply it to prove triangles are right and to problem solve. This is the second...
1 In 1 Collection
Lesson Planet

Geometry Sample Problems

For Students 8th - 11th Standards
I'd like to prove that this worksheet has a lot to offer. Seven problems using triangles and parallelograms practice the traditional method of a two-column proof. After the worksheet is some practice problems that show worked out...
Lesson Planet

Parallel Lines Proofs Practice

For Students 8th - 11th Standards
Here is a activity that lines up perfectly with the skills needed to finish a geometric proof. Eleven problems are given to see if learners can prove that lines are parallel or angles are congruent. 
1 In 1 Collection
EngageNY

Scale Factors

For Students 9th - 10th Standards
Is it bigger, or is it smaller—or maybe it's the same size? Individuals learn to describe enlargements and reductions and quantify the result. Lesson five in the series connects the creation of a dilated image to the result. Pupils...