Q.Tell me why you call it a tri-angle.

A.We call it a tri-angle because it has three angles.

Q.What do you mean by equal?
A.When the three sides are of the same length.

Q.Have you any thing else to observe upon this?
A.Yes, all its angles are acute.
_Isoceles Triangle_.
Q.What is this?
A.An acute-angled isoceles triangle.

Q.What does acute mean?
A.When the angles are sharp.