Obtuse angles

Date: Thu, 10 Nov 94 16:12:00 PST
From: "Neufeld, Joyce CLK-STAFF"
Subject: lst grader's want to know

We are learning about geometric shapes.  One of my students 
wants to know what is an obtuse angle?

Joyce Neufeld
First Grade Teacher
Clark Elementary         (for Douglas Sherbon)

Date: Fri, 11 Nov 1994 12:19:04 -0500 (EST)
From: Dr. Ken
Subject: Re: lst grader's want to know

Hello there in Ms. Newfield's class!!

You've sent in a great question.  I'm VERY impressed that you're learning
about different kinds of angles in first grade!  Good work.

You know what an angle is, right?  Well, an obtuse angle is just one special
kind of angle.  If we look at all different kinds of angles, we can divide
them up into three groups:  

1)  Those that look like this:

                    |
                    |
                    |
                    |
                    |
                    |
                    |
                    |
                    |____________________

These angles are called Right Angles.  If you look at the corner of a
regular sheet of paper, or at the corner of the table or a blackboard,
you'll find a right angle.  Where else can you find a right angle?  I bet
there are some all around you in the classroom!

2)  Angles that are smaller than right angles, like this:

                                        /
                                       /
                                      /
                                     /
                                    /
                                   /
                                  /
                                 /
                                /
                               /
                              /
                             /
                            /
                           /______________________

Note that when I say SMALLER, I don't mean that the lines that make them up
are shorter, but that it comes to a sharper point than a right angle.  All
of these angles are called ACUTE angles.  Can you find some around you?  I
be there are some.

3)  The angles that are bigger than right angles, which might look like this:

\
 \
  \
   \
    \
     \
      \
       \
        \
         \
          \
           \
            \____________________________

See how these two lines don't come to a very sharp point?  My friend, all
these angles that don't come to as sharp a point as a right angle are called
OBTUSE angles.  Can you find some examples of obtuse angles around you?

Have fun!

-Ken "Dr." Math