Identify triangles by their angle measures and side lengths by looking at and measuring angle measures and side lengths. Use Cabri Jr. to construct various triangles, then manipulate the construction to create the 6 types of triangles,...

This presentation is intended to accompany an entire unit and covers a wide variety of concepts. Counting on, counting back, symmetry, properties of 2-D shapes, completing symmetrical patterns, and measuring angles are all covered.

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. 

What does a geometric farmer drive? A protractor, of course! A set of assessment worksheets prompts learners to use a protractor as they measure angles, name angles, and identify lines. Use the video as a way to...

Learners identify and create angles. In this angle measurement lesson, students use sticks to make models of angles, then measure and name each angle.

In this right triangle trigonometry instructional activity, students use trigonometric ratios to determine the length of a missing side of a triangle or to find a specified angle measurement. This four-page instructional activity...

Why was the obtuse angle upset? Because it was never right! A valuable resource is loaded with background information on types of angles and lines. Learners review the characteristics of parallel, perpendicular, and...

Acute or obtuse? Seems right to me! As scholars explore the simulation, they investigate angle measures. Questions ask them to classify the angles using correct naming conventions.

Observe the change in the trigonometric ratios as angles vary. An interactive provides the values of trigonometric ratios for both acute angles in a right triangle. Pupils create a right triangle to match given criteria and find the...

In these angles and geometry worksheets, learners learn about different kinds of angles, angle measurement, and other geometry facts. Students complete 15 questions.

In this geometry activity, 10th graders use right triangle trigonometry to solve application problems in which they find the measure of the missing angle in a right triangle.  The two page activity contains five free response...

Learners estimate angle measures in this this estimating angle measures lesson. They use an application on their graphing calculator that shows various settings involving angles and then they estimate the angle measure of a clock's...

Middle schoolers explore angle measure as they estimate angle measure and measure and draw angles of less than 360 degrees. The lesson emphasizes the use of estimation when measuring angles.

In this right triangles and circles worksheet, students solve 4 short answer problems. Students describe a right triangle formed by point on a circle and an angle measure.

In this geometry activity, 10th graders use right triangle trigonometry to find the missing angle measure or side length in right triangles. The one page interactive activity contains ten questions. Answers and hints are included. 

Inscribed angles are central to the instructional activity. Young mathematicians build upon concepts learned in the previous instructional activity and formalize the Inscribed Angle Theorem relating inscribed and central angles. The...

It doesn't matter whether secant lines intersect inside or outside the circle, right? Scholars extend concepts from the previous lesson to investigate angles created by secant lines that intersect at a point exterior to the circle....

Even though there is a wide variety of different triangles in the world, knowing a single equation allows us to find the area of each and every one of them. Follow along with this step-by-step presentation as Zoe clearly models how to...

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...

Learn how to measure acute, right, and obtuse angles with a protractor. After reviewing the way the protractor works, fourth graders measure nine angles on their own. For extra practice, have them measure different angles in their...

In this classification of triangles activity, 10th graders identify and complete 8 different problems that include determining the measurement and perimeter of various types of triangles. First, they color all right, acute, and obtuse...

Over the course of 18 problems, learners identify angles as complementary, supplementary, vertical or adjacent. They name relationships in angles such as alternate interior, corresponding, and alternate exterior angles. They apply the...

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...

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...