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eBook
Mathigon

Mathigon: Geometry: Triangles and Trigonometry: Pythagoras' Theorem

For Students 9th - 10th Standards
Pythagoras' Theorem: In any right-angled triangle, the square of the length of the hypotenuse (the side that lies opposite the right angle) is equal to the sum of the squares of the other two sides. (A+B=C)
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Srt Shortest Line Segment From a Point P to a Line L

For Teachers 9th - 10th Standards
In this task, students develop an understanding that the shortest path from a point to a line always meets the line at a right angle. Aligns with G-SRT.C.8.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Srt Pythagorean Theorem

For Teachers 9th - 10th Standards
The purpose of this task is to prove the Pythagorean Theorem using similar triangles. Aligns with G-SRT.B.4.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Srt, G Mg How Far Is the Horizon?

For Teachers 9th - 10th Standards
Some friends are at the beach looking out onto the ocean on a clear day and they wonder how far away the horizon is. A second problem asks how far the horizon would be from the top of a mountain. Students must also answer a question...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Srt Ask the Pilot

For Teachers 9th - 10th Standards
In the July 2013 issue of United Airlines' Hemisphere Magazine, a pilot responded to a question about how far in the distance he could see at different altitudes. The solution involved right triangles, lines of tangency to a circle, and...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe Slopes and Circles

For Teachers 9th - 10th Standards
The purpose of this task is to lead students through an algebraic approach to a well-known result from classical geometry, namely, that a point X is on the circle of diameter AB whenever angle AXB is a right angle. This consists of...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe Explaining the Equation for a Circle

For Teachers 9th - 10th Standards
This problem examines equations defining different circles in the x-y plane. Students must use the Pythagorean Theorem to find equations whose solutions are points on the circle and explain why they work. Includes a GeoGebra worksheet...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe Squares on a Coordinate Grid

For Teachers 9th - 10th Standards
The purpose of this task is to use the Pythagorean Theorem and knowledge about quadrilaterals in order to construct squares of different sizes on a coordinate grid. Aligns with G-GPE.B.7.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe Defining Parabolas Geometrically

For Teachers 9th - 10th Standards
The purpose of this task is to show that the points on a parabola can be characterized by being equidistant from a point (the focus) and a line (the directrix). Aligns with HSG-GPE.A.2.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe Triangle Perimeters

For Teachers 9th - 10th Standards
Students are shown two triangles touching points on a coordinate grid and are asked to answer questions about their perimeters. The purpose of this task is to apply the Pythagorean theorem to calculate distances and areas. Aligns with...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: F Tf Special Triangles 1

For Teachers 9th - 10th Standards
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: F Tf Special Triangles 2

For Teachers 9th - 10th Standards
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
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Handout
Other

Mathway: Algebra Formulas

For Students 9th - 10th Standards
Comprehensive resource provides algebra formulas for exponents, absolute value, factoring Pythagorean Theorem, linear equations, quadratic formula, distance formula, midpoint formula, and slope of a line through two points.
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Unit Plan
TED Talks

Ted: Ted Ed: How Many Ways Are There to Prove the Pythagorean Theorem?

For Students 9th - 10th Standards
Betty Fei details these three famous Pythagorean theorem proofs.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g.b.7: Spiderbox

For Teachers 7th - 9th
The purpose of this task is for students to work on their visualization skills and to apply the Pythagorean Theorem. Aligns with 8.G.B.7.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g a Rectangle in the Coordinate Plane

For Teachers 8th Standards
In this task, 8th graders are shown a picture of a quadrilateral on a coordinate grid and are asked to use the Pythagorean Theorem to find lengths and to explain why the quadrilateral is a rectangle. Aligns with 8.G.B.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Glasses

For Teachers 8th Standards
In this task, 8th graders are presented with a drawing of three glasses of different shapes and their measurements. They are asked to make several calculations that require the application of the Pythagorean Theorem and volume formulas....
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g, G Srt Points From Directions

For Teachers 9th - 10th Standards
For this problem, students must carefully read the description of a triangle and a fourth point that lies outside it and draw a picture to represent the problem. They must then use the Pythagorean Theorem to find side lengths. Aligns...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Area of a Trapezoid

For Teachers 8th Standards
Eighth graders are given various dimensions of a trapezoid and are asked to find its area. This requires them to use the Pythagorean Theorem and to decompose the trapezoid into other polygons. Aligns with 8.G.B.7.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Two Triangles' Area

For Teachers 8th Standards
In this task, 8th graders are given the dimensions of two isosceles triangles and are asked to compare their areas. They must draw them and use the Pythagorean Theorem and the triangle area formula to solve the problem. Aligns with 8.G.B.7.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Finding Isosceles Triangles

For Teachers 8th Standards
This task asks students to examine three triangles in the coordinate plane and explain why they are isosceles triangles. Aligns with 8.G.B.8.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Converse of the Pythagorean Theorem

For Teachers 8th Standards
This task asks students to explain what the Pythagorean Theorem and its converse are, how the converse works, and why it is true. Aligns with 8.G.B.6.
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Bird and Dog Race

For Teachers 8th
In this race between a bird and a dog, 8th graders are provided with information about their starting locations on a map and their speeds. They are asked to predict a winner, draw the paths they might follow, decide how to determine who...
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Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g.7 Running on the Football Field

For Teachers 8th Standards
This task asks students to apply the Pythagorean Theorem to find the approximate number of yards two players ran during a football game and compare their distances. Aligns with 8.G.B.7.