2.  Four Angles
 Acute
 Right
 Obtuse
 Straight

3.  An acute angle is anything angle that is
less than 90 degrees.

4.  A right angle is any angle that is exactly
90 degrees.

5.  An obtuse angle is any angle that is
more than 90 degrees but less than 180
degrees.

6.  A straight angle is any angle that equals
180 degrees.

7.  Bike spokes

8.  Exit sign
 Four right angles

9.  Door hinge

10.  Table edge

11.  http://points.donmcleer.com/category/
design/
 http://etc.usf.edu/clipart/38500/38572/a
ngleacute_38572_lg.gif
 http://oald8.oxfordlearnersdictionaries.c
om/dictionary/right-angle
 http://www.mathsisfun.com/definitions/o
btuse-angle.html
 http://www.mathsisfun.com/geometry/st
raight-angle.html