. Q. Are there any other kind of
scalene triangles? A. Yes, there is a right-angled scalene triangle,
which has one right angle. Q. What else? A. An obtuse-angled scalene
triangle, which has one obtuse angle. Q. Can an acute triangle be an
equi-lateral triangle? A. Yes, it may be equilateral, isoceles, or
scalene. Q. Can a right-angled triangle, or an obtuse-angled triangle,
be an equilateral? A. No; it must be either an isoceles or a scalene
triangle.

_Square_.

Q. What is this? A. A square. Q. Why is it called a square? A. Because
all its angles are right angles, and its sides are equal. Q. How many
angles has it? A. Four angles. Q. What would it make if we draw a
line from one angle to the opposite one? A. Two right-angled isoceles
triangles. Q. What would you call the line that we drew from one angle
to the other? A. A diagonal. Q. Suppose we draw another line from the
other two angles. A. Then it would make four triangles.

_Pent-agon_.

Q. What is this? A. A regular pentagon. Q. Why is it called a
pentagon? A. Because it has five sides and five angles. Q. Why is it
called regular? A. Because its sides and angles are equal. Q. What
does pentagon mean? A. A five-sided figure. Q. Are there any other
kinds of pentagons? A. Yes, irregular pentagons? Q. What does
irregular mean? A. When the sides and angles are not equal.

_Hex-agon_.

Q. What is this? A. A hexagon. Q. Why is it called a hexagon? A.
Because it has six sides and six angles. Q. What does hexagon mean? A.
A six-sided figure. Q. Are there more than one sort of hexagons? A.
Yes, there are regular and irregular. Q. What is a regular hexagon?
A. When the sides and angles are all equal. Q. What is an irregular
hexagon? A. When the sides and angles are not equal.

_Hept-agon_.

Q. What is this? A. A regular heptagon. Q. Why is it called a
heptagon? A. Because it has seven sides and seven angles. Q. Why is it
called a regular heptagon? A. Because its sides and angles are equal.
Q. What does a heptagon mean? A. A seven-sided figure. Q. What is
an irregular heptagon? A. A seven-sided figure, whose sides are not
equal.

_Oct-agon_.

Q. What is this? A. A regular octagon. Q. Why is it called a regular
octagon? A. Because it has eight sides and eight angles, and they are
all equal. Q. What does an octagon mean? A. An eight-sided figure. Q.
What is an irregular octagon? A. An eight-sided figure, whose sides
and angles are not all equal. Q. What does an