Virginia Department of Education
Angles in Polygons
Polygons — it's all about the angles. Groups work with dynamic geometry software to find the sum of the measures of the angles of various polygons. After finding the information for several polygons, the groups generate a formula that...
EngageNY
Sine and Cosine of Complementary Angles and Special Angles
Building trigonometric basics here will last a mathematical lifetime. Learners expand on the previous lesson in a 36-part series by examining relationships between the sine and cosine of complementary angles. They also review the...
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...
Mathed Up!
Angles: Parallel Lines
Viewers are presented with seven problems with parallel lines and angle relationships and must use the given information to find the measures of specific angles. To finish, they explain their process in finding the measures in the...
EngageNY
Unknown Angle Proofs—Proofs of Known Facts
Lead the class in a Greek history instructional activity 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...
EngageNY
Unknown Angle Problems with Inscribed Angles in Circles
We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson plan then...
Project Maths
Introduction to Angles
Approach the activity from the right angle. A discussion-based activity leads helps learners understand angles in terms of rotation. Individuals use manipulatives to explore the properties of angles and learn how to name them. The...
Curated OER
Determining Angle Measure with Parallel Lines
Young scholars observe and solve examples of corresponding angle postulates, alternate interior angle theorems, and exterior and consecutive angles. They complete the Determining Angle Measure With Parallel Lines worksheet.
Curated OER
Angle Relationships
Tenth graders explore the angle relationships that exist when two lines intersect. In this geometry lesson, 10th graders estimate the measure of given angles and use their graphing calculator tools. Students use this knowledge to find...
Curated OER
Angle Measurement 2
In this angle measurement worksheet, 10th graders solve 24 problems that include determining the measurement of various angles. First, they define each angle and the specific type that is shown in each. Then, students determine the...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
EngageNY
Unknown Angles
How do you solve an equation like trigonometry? Learners apply their understanding of trigonometric ratios to find unknown angles in right triangles. They learn the meaning of arcsine, arccosine, and arctangent. Problems include...
Concord Consortium
Sharp-Ness of Bends
Define the sharpest in the group. Given a section of a trail map, pupils determine a method to measure the sharpness of each turn in the path. Individuals then determine what modifications to their formulas to make to find the sharpness...
CK-12 Foundation
Proofs: Angle Pairs and Segments—The Three Angle Problem
Finding the sum of the measures of three angles is easy, unless you have no clue what the measures are. Learners use an interactive diagram to see a geometric problem in a different way. A set of challenge questions takes them through...
EngageNY
Solving for Unknown Angles Using Equations II
The third activity in the series of 29 asks learners to identify types of angles to verify angle relationships. They find unknown measures using vertical, adjacent, complementary, supplementary, and 360-degree angles.
EngageNY
Solving for Unknown Angles Using Equations
They say a picture is worth a thousand words—and your pupils may agree after this instructional activity! They read a geometric description and create a diagram from that description. Their diagrams help them find unknown measures based...
EngageNY
Solving for Unknown Angles Using Equations III
Challenge your classes to combine geometric and algebraic concepts with an activity that builds on concepts learned in the first three lessons of the series. The fourth part asks scholars to identify geometric angle relationships and use...
Curated OER
Similarity and Dilations - Discover Properties of Similar Figures
Learners investigate properties of similar figures. In this properties of similar figures lesson, pupils construct similar figures using Cabri Jr. They dilate their figure to create a similar one, and discuss the relationships between...
Curated OER
Cabri Jr. Inscribed Angles
Young scholars construct inscribed angles using Cabri Jr. They draw a circle on their graphing calculator, then construct an inscribed angle and measure its angle measures. Learners drag the inscribed angle around the circle. They make...
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...
Flipped Math
Addition Postulate
Add a little algebra to the geometry. Class members learn about the Addition Postulate for segments and angles. The pupils use their knowledge of solving equations to find lengths of segments and measures of angles. Individuals apply...
Mathed Up!
Bearings
Keep the math straight and true. Using information learned about angle relationships, pupils determine drawn bearings, or draw a line with a given bearing. The accompanying video provides the definition of a bearing and its three...
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...
Curated OER
Finding Angles, Volume, Area, and Perimeter
Elementary schoolers complete word problems dealing with the different kinds of measurements of different shapes. They solve 10 problems including perimeter, angles, volume, and more.