This lesson introduces and defines vertical angles. It is 2 of 11 in the series titled "Vertical Angles."

This lesson provides practice problems that apply the triangle exterior angles theorem. It is 5 of 6 in the series titled "Triangle Exterior Angles Practice."

This lesson introduces and defines vertical angles.

This lesson defines the phrase right angle. It is 1 of 14 in the series titled "Right Angle."

Learners explore the special angles for the six trigonometric functions. The special angles can be used to solve trigonometry problems. The table gives the values of sine, cosine, tangent, cotangent, secant, and cosecant for special angles.

This lesson introduces the exterior angles theorem of triangles. It is 3 of 5 in the series titled "Triangle Exterior Angles Theorem."

This lesson provides practice problems that involve the sum of the interior angles of triangles. It is 5 of 6 in the series titled "Triangle Interior Angles Practice."

This lesson provides practice problems that involve the sum of the interior angles of triangles. It is 1 of 6 in the series titled "Triangle Interior Angles Practice."

This lesson demonstrates how to use triangles to determine the sum of the interior angles of a polygon. It is 1 of 5 in the series titled "Using Triangles to Find the Sum of Interior Angles."

This lesson explains how the central angle can be used to determine the area of a sector and presents several practice problems. Includes answers and a short quiz. It is 2 of 5 in the series titled "Finding the Area of a Sector Using the...

This site gives the definition of an acute triangle, along with examples and related terms.

This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon. It is 2 of 4 in the series titled "Using Right...

This site provides a general definition, complete with a diagram, of an angle bisector.

Mathwords provides a brief definition and diagram of an angle bisector.

Three trig tables are provided for student and teacher reference. The first table lists the sine, cosine, tangent, secant, cosecant, and cotangent values of all whole-number angles from 0 to 90. The radian equivalent (to four decimals)...

A map of Scotland, England and Wales showing the settlements of the Saxons and Angles from the landing of Hengist and Horsa at Ebbsfleet on the shores of the Isle of Thanet (AD 449) to the Saxon Heptarchy (AD 626). "By these invasions...

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

An interactive map that shows the countries of the Middle East in 2003. Gives information such as population, government, and history about each country.

This lesson will demonstrate how to locate the height in an obtuse, right, and acute triangle. It is 4 of 5 in the series titled "Triangle Height."

This lesson will demonstrate how to find the area and radius of a circle when given the sector area and central angle measure. It is 4 of 8 in the series titled "Sector Area of a Circle."

This lesson gives a tutorial on the measure of an angle. Includes sample problems and solutions.

From a wonderful compilation of 10,000 images by Mary Ann Sullivan of Bluffton College. There are images of the exterior of the National Gallery of Art from all angles. This building is designed by I.M. Pei, the 1983 selection for the...

Every side and angle of the Arch of Titus is pictured at this site. Just choose which side you want to see, and click on it. Voila! You won't find more pictures at one site on any one piece of architecture than you will at this one!

This online album features incredible photographs of tornadoes and storm fronts taken from different angles and perspectives.