octave mean? A. Eight
notes in music.

_Non-agon_.

Q. What is this? A. A nonagon. Q. Why is it called a nonagon? A.
Because it has nine sides and nine angles. Q. What does a nonagon
mean? A. A nine-sided figure. Q. What is an irregular nonagon? A. A
nine-sided figure whose sides and angles are not equal.

_Dec-agon_.

Q. What is this? A. A regular decagon. Q. What does a decagon mean? A.
A ten-sided figure. Q. Why is it called a decagon? A. Because it has
ten sides and ten angles, and there are both regular and irregular
decagons.

_Rect-angle or Oblong_.

Q. What is this? A. A rectangle or oblong. Q. How many sides and
angles has it? A. Four, the same as a square. Q. What is the
difference between a rectangle and a square? A. A rectangle has two
long sides, and the other two are much shorter, but a square has its
sides equal.

_Rhomb_.

Q. What is this? A. A rhomb. Q. What is the difference between a rhomb
and a rectangle? A. The sides of the rhomb are equal, but the sides of
the rectangle are not all equal. Q. Is there any other difference? A.
Yes, the angles of the rectangle are equal, but the rhomb has only its
opposite angles equal.

_Rhomboid_.

Q. What is this? A. A rhomboid. Q. What is the difference between a
rhomb and a rhomboid? A. The sides of the rhomboid are not equal, nor
yet its angles, but the sides of the rhomb are equal.

_Trapezoid_.

Q. What is this. A. A trapezoid. Q. How many sides has it? A. Four
sides and four angles, it has only two of its angles equal, which are
opposite to each other.

_Tetragon_.

Q. What do we call these figures that have four sides. A. Tetragons,
_tetra_ meaning four. Q. Are they called by another name? A. Yes,
they are called quadrilaterals, or quadrangles. Q. How many regular
tetragons are among those we have mentioned? A. One, that is the
square, all the others are irregular tetragons, because their sides
and angles are not all equal. Q. By what name would you call the whole
of the figures on this board? A. Polygons; those that have their sides
and angles equal we would call regular polygons. Q. What would you
call those angles whose sides were not equal? A. Irregular polygons,
and the smallest number of sides a polygon can have is three, and the
number of corners are always equal to the number of sides.

_Ellipse or Oval_.

Q. What is this? A. An ellipse or an oval. Q. What shape is the top or
crown of my bat? A. Circular. Q. What shape is t