2 Chapter 1 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. 3Copyright (c) 2005 John Wiley & Sons, Inc.Chapter 1 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. 4Copyright (c) 2005 John Wiley & Sons, Inc. Learning Objectives.
Notice it always remains an equiangular triangle. The angles A,B and C always remain equal in measure. An equiangular triangle is a triangle where all three interior angles are equal in measure. Because the interior angles of any triangle always add up to 180Â°, each angle is always a third of that, or 60Â° The sides of an equiangular triangle are all the same length (congruent), and so an equiangular triangle is really the same thing as an equilateral triangle. See Equilateral Triangles. Properties
Radians. The other common measurement for angles is radians. For this measurement, consider the unit circle (a circle of radius 1) whose center is the vertex of the angle in question. Then the angle cuts off an arc of the circle, and the length of that arc is the radian measure of the angle. It is easy to convert between degree measurement and radian measurement. The circumference of the entire circle is 2 Ï, so it follows that 360Â° equals 2 Ï radians.