Microsoft Office Standard 2010 adjacent angles.htm
 

,Office Home And Student 2010
Subject: Adjacent Angles

Katherine Keys
Middle School
Teacher

Can a straight angle be an adjacent angle to another angle?
Hi Katherine,Microsoft Office Standard 2010,
The answer depends on your definitions of both "angle" and
"adjacent angles." I would define an angle to be the measure of the
rotation about the vertex that brings the first arm of the angle into the
second. I would then define two angles to be adjacent if (a) they share
the vertex and (b) the second arm of the first angle coincides with the
first arm of the second angle. (This simplifies the definition of angle
addition.) With this definition the angles could be positive or negative
and could measure more than 360 degrees; there would be no restrictions as
to what angles could be adjacent.
Euclid did not define "angle measure",Office 2007 Standard Key, and he did not distinguish
between positive and negative angles. (Thus an angle of minus 30 degrees
would have no meaning to him.) For him the maximum angle was probably the
straight angle. Most modern texts allow angles to exceed 180 degrees,Microsoft Office Pro 2007, so
that it would make good sense to have a straight angle adjacent to another
angle, as long as they share a vertex and have a common arm that lies
between the two outer arms.
Cheers,Windows 7 Discount,
Chris Go to Math Central