Article reports on the discovery of a supermassive object 90 million light-years from Earth that may be an orphan black hole.

This online exhibit from the American Antiquarian Society is filled with lithographs, catalogs, trade cards, and product labels that show how food production and distribution expanded in the last half of the 19th century. Be sure to...

[Free Registration/Login Required] Students are given triangles and angles and are to determine which triangles are congruent. Click learn more to watch a video and challenge me to try a practice question.

Read an article from the Arkansas Archaeology Survey that traces a probable route of Hernando de Soto in what is now Arkansas. Evidence has been found especially in the Parkin site in northeast Arkansas.

Portraits of thirty-one Worcester residents. Among the names is Isaiah Thomas.

Find guidelines to help you "solve" triangles, which means finding the value of missing sides and angles. Provided are examples of six scenarios in which you can solve a triangle's missing measurements, as well as relevant equations,...

In this lesson on congruent triangles, students explore how to use postulates to identify if triangles are congruent by SSS, SAS, ASA, and AAS.

This activity works with a PowerPoint presentation to have students answer questions as to what method a pair of triangles can be proven congruent: SSS, SAS, ASA, AAS, HL.

Use the angle bisector theorem to find missing side lengths in triangles.

Learn all about the basic properties of a cone. This lesson targets the ASA congruence theorem using real-life examples and has interesting interactive practice questions.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students the relationship between opposite angles and sides in triangles and how to use this relationship to compare triangles. students examine...

[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two triangles are congruent with the Angle-Side-Angle and Angle-Angle-Side shortcuts. Students examine guided notes, review guided...

[Free Registration/Login may be required to access all resource tools.] This concept introduces students to the ASA and AAS Triangle Congruence shortcuts. Students examine guided notes, review guided practice, watch instructional videos...

See how triangles are congruent where all corresponding angle pairs and sides are the same.

[Free Registration/Login may be required to access all resource tools.] Provides an overview of triangle congruence, including key terms, properties of congruent triangles, triangle postulates and theorems, and special triangles.

This study guide on angles and transversals covers key terms, angle types formed by transversals, postulates and theorems about transversals, and how to prove if lines are parallel or perpendicular. It is available for download with free...

[Free Registration/Login may be required to access all resource tools.] Finding unknown sides in a triangle using other sides and angles.

[Free Registration/Login may be required to access all resource tools.] Find the unknown side of a triangle when two angles and a side are known.

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)

In this task, students must prove that angles and triangles are congruent and that a parallel line passes through the midpoints of two sides of the larger triangle. Aligns with G-SRT.B.4.

Defines the Pythagorean Theorem, and demonstrates how to use this Theorem in connection with right-angled triangles.

Use the triangle congruence criteria SSS, SAS, ASA, and AAS to determine that two triangles are congruent. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

As a resource for teachers, an activity of how to connect Venn Diagrams with the five methods of proving triangles congruent - SSS, SAS, ASA, AAS, HL - is explained.

Use the triangle congruence criteria SSS, SAS, ASA, and AAS to determine that two triangles are congruent.