EngageNY
Similarity and the Angle Bisector Theorem
Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...
EngageNY
Unknown Angle Proofs—Proofs with Constructions
Provide your emerging mathematicians with the tools to learn as they incorporate auxiliary lines to solve unknown angle proofs in this continuing segment. They decipher information from a diagram to uncover the missing pieces and...
EngageNY
Congruence Criteria for Triangles—AAS and HL
How can you prove it? Guide classes through an exploration of two possible triangle congruence criteria: AAS and HL. Learners connect this criteria to those previous learned and also explore criteria that does not work. The lesson plan...
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 then...
Curated OER
Supplementary, Complementary, and Vertical Angles
By using circles that they cut out and label themselves, learners literally "get a grip" on the angles they identify: supplementary, complementary, and vertical. They solve missing measurements based on properties of supplementary,...
CK-12 Foundation
Conversion between Degrees and Radians: Clock Angles and Measures
It's 3:30, what radian is it? Pupils create clock angles on a clock and determine the radian measure to the minute hand. They then use a conversion factor to convert from one measurement to another.
Curated OER
Angles Activities
A series of geometry worksheets have mathematicians constructing, dissecting, overlapping, and measuring as they analyze angles in various contexts. Learners use symmetry and reflections in a compass rose to write instructions on...
CK-12 Foundation
Complementary Angles: Corner Kick
Soccer is all about angles. Young mathematicians use an interactive to correctly position the path of a soccer ball so that it reaches the goal. They consider complementary angles when answering a set of challenge questions.
CK-12 Foundation
Complementary Angles
Here's an interactive that complements your lesson plans. Users of the resource adjust one of the angles in a complementary set to see how it affects the other. A set of challenge questions assesses understanding.
Curated OER
Measuring Angles in a Quadrilateral
High schoolers explore quadrilaterals in this geometry lesson. They will draw a quadrilateral, measure the angles, and find the sum of the measures of the interior angles using Cabri Jr. The interactive capabilities of Cabri Jr. allow...
Curated OER
All Angles (A)
In this measuring angles review worksheet, learners use their math skills to solve 6 problems that require them to estimate and measure each of the 6 angles.
Curated OER
Angles measure and classify
In this angles worksheet, students measure angles with a protractor and figure out if it is acute, right, obtuse, or straight. Students complete 6 problems.
K12 Reader
Kinds of Angles
Have you ever wondered how circles and angles relate to each other? Read a passage about right angles, acute angles, and obtuse angles, and answer reading comprehension questions about the information you learn.
Illustrative Mathematics
Sum of Angles in a Polygon
How can learners use algebra to solve a geometry problem? Help learners create an equation that shows the relationship between the number of sides of a polygon and the sum of the interior angles. Students are asked to divide the...
CK-12 Foundation
Angle Classification: Crazy Quilt
There's more to a quilt than just a pretty pattern—there's geometry! Explore angle classification using an artistic approach to show your class that quilt designs are really just intricate geometric patterns. Here, scholars create a...
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...
Curated OER
Complementary and Supplementary Angles
Your geometry learners determine the measure of remaining angles in sets of three given that the other two are complementary or supplementary. From a diagram, they identify which angles are supplementary, complementary or congruent from...
Curated OER
Angle Relationships
Tenth graders explore the angle relationships that exist when two lines intersect. In this geometry instructional activity, 10th graders estimate the measure of given angles and use their graphing calculator tools. Students use this...
Curated OER
Relationship between Exterior and Remote Interior Angles in a Triangle
In this triangle activity set, 9th graders find the relationship between the exterior and remote interior angles in triangles. They determine the formula, and apply it in 15 problems. They use a compass as needed to measure angles.
Curated OER
Measuring Angles & Segments
Students view a PowerPoint for a warm-up instructional activity. They practice measuring around the classroom, measuring such things as the length and width of a desk, pencil, door, and book. Students use a website to practice measuring...
Curated OER
Shapes and Designs Investigation
Sixth graders estimate angle measures and angle theroms. In this online interactive geometry lesson, 6th graders review types of angles, investigate angle theroms, and explore nonadjacent angles.
Curated OER
Geometry and Measurement Pre-Test
Use this comprehensive pre-instruction assessment tool to focus your teaching where your class needs it most. Multiple choice questions assess your budding geometers' conceptual and vocabulary knowledge, but they do not solve any...
CK-12 Foundation
Six Trigonometric Functions and Radians: Degrees to Radians and Back Again!
How do degrees relate to radians? The interactive allows pupils to manipulate the size of an angle in a unit circle to help see that relationship. Users determine the radian measure for given degree measures of angles, realizing the...
CK-12 Foundation
Rotations in Radians: Clock Conundrum
Pupils use an interactive clock to set specific times. They apply math to an everyday task as they determine the measure of the angle formed by the hands in degrees and in radians.