Rather than dividing a circle into some number of segments (like 360 degrees), mathematicians often prefer to measure angles using the circumference of a unit circle - a circle with radius 1. This way of measuring angles is called...

This lesson expands your knowledge about circles by learning about the segment of a circle, which will include its mathematical definition, area of the segment, types of segments in a circle, theorems based on a segment of a circle, and...

For this task, students are shown a unit circle in a plane and an angle measured from the x-axis. They must determine the coordinates of the line segment for the angle and answer a question about the sum of the coordinates. The purpose...

This fourth-grade geometry lesson teaches the definitions for a line, ray, angle, acute angle, right angle, and obtuse angle. We also study how the size of the angle is ONLY determined by how much it has "opened" as compared to the whole...

This University of St. Andrews site contains information on the life of Heron as well as his accomplishments.