Shodor Education Foundation
Triangle Area
While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...
EngageNY
Awkward! Who Chose the Number 360, Anyway?
Don't give your classes the third degree. Use radians instead! While working with degrees, learners find that they are not efficient and explore radians as an alternative. They convert between the two measures and use radians with the...
EngageNY
More on the Angles of a Triangle
Angles and triangles: they're all connected. Uncover the connections between angles in triangles. Scholars learn how to find both exterior and interior angle measures in triangles. The lesson emphasizes the vocabulary related to these...
EngageNY
Reflections
Facilitate creativity in your math class as individuals learn the definition of a geometric reflection and correctly construct a model, as well as its reflected image. They use a perpendicular bisector and circles to elaborate on...
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Applying the Laws of Sines and Cosines
Breaking the law in math doesn't get you jail time, but it does get you a wrong answer! After developing the Law of Sines and Cosines in lesson plan 33 of 36, the resource asks learners to apply the laws to different situations. Pupils...
Curated OER
The Effect of Math Anxiety on Cardiovascular Homeostasis
Using a pulse monitor, learners will measure a resting pulse, take a math test, and then measure the pulse again. They analyze the change in pulse and compare it to performance on the test. This multi-purpose lesson plan can be used in a...
Charleston School District
The Sum of Angles in a Triangle
An informative lesson contains a brief explanation of how the sum of the angles of a triangle is a line. The lesson continues with determining the missing angle in a triangle, or solving for a variable. Using the sum of the...
Charleston School District
Parallel Lines Cut by a Transversal
Pupils study angle measurements between different types of angles associated with parallel lines and transversals. The independent practice asks pupils to identify the types of angles in a diagram and to determine the measure of...
EngageNY
Solve for Unknown Angles—Angles and Lines at a Point
How do you solve for an unknown angle? In this sixth installment of a 36-part series, young mathematicians use concepts learned in middle school geometry to set up and solve linear equations to find angle measures.
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Unknown Angle Proofs—Proofs of Known Facts
Lead the class in a Greek history lesson plan with a geometric twist. Pupils relate a short video about geometric properties to modern-day methods of solving for unknown angles. They discuss parallel line theorems and...
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Making Scale Drawings Using the Ratio Method
Is that drawn to scale? Capture the artistry of geometry using the ratio method to create dilations. Mathematicians use a center and ratio to create a scaled drawing. They then use a ruler and protractor to verify measurements.
EngageNY
Proving the Area of a Disk
Using a similar process from the first lesson in the series of finding area approximations, a measurement resource develops the proof of the area of a circle. The problem set contains a derivation of the proof of the circumference...
Virginia Department of Education
Lines and Angles
Explore angle relationships associated with transversals. Pupils construct parallel lines with a transversal and find the measures of the angles formed. They figure out how the different angles are related before constructing...
Curated OER
Statistics Canada
Students practice using graphing tools to make tables, bar charts, scatter graphs, and histograms, using census data. They apply the concept of measures of central tendency, examine the effects of outliers. They also write inferences and...
EngageNY
Informal Proofs of Properties of Dilations
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...
EngageNY
The Converse of the Pythagorean Theorem
Is it a right triangle or not? Introduce scholars to the converse of the Pythagorean Theorem with a lesson plan that also provides a proof by contradiction of the converse. Pupils use the converse to determine whether triangles with...
EngageNY
Real-World Area Problems
Not all structures take the shape of a polygon. The 21st lesson in a series of 29 shows young mathematicians they can create polygons out of composite shapes. Once they deconstruct the structures, they find the area of the composite figure.
EngageNY
Solve for Unknown Angles—Transversals
Lead your class on an exciting journey through the world of math as they review geometry facts and solve for unknown angles. They learn how to use auxiliary lines and congruent angles to correctly complete each practice problem...
Charleston School District
Pythagorean Theorem and Converse
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...
EngageNY
More About Similar Triangles
Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...
EngageNY
Rotations of 180 Degrees
What happens when rotating an image 180 degrees? The sixth lesson in the series of 18 takes a look at this question. Learners discover the pattern associated with 180-degree rotations. They then use transparency paper to perform the...
EngageNY
Cones and Spheres
Explore methods for finding the volume of different three-dimensional figures. The 20th lesson in the 25-part series asks learners to interpret diagrams of 3-D figures and use formulas to determine volume. Scholars must use the...
EngageNY
Converse of the Pythagorean Theorem
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...
EngageNY
More on Modeling Relationships with a Line
How do you create a residual plot? Work as a class and in small groups through the activity in order to learn how to build a residual plot. The activity builds upon previous learning on calculating residuals and serves as a...