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
An equilateral triangle has three congruent sides, and is also an equiangular triangle with three congruent angles that each meansure 60 degrees. To find the height we divide the triangle into two special 30 - 60 - 90 right triangles by drawing a line from one corner to the center of the opposite side. This segment will be the height, and will be opposite from one of the 60 degree angles and adjacent to a 30 degree angle.