In triangles the exterior
angle at one vertex is
equal to the sum of the
internal angles at the
other two vertices.
Angles around a point
add up to 360cm.
Triangles have an
interior angle that is a
reflex angle.
Opposite Angles are
equal.
A right angle is the
opposite of a left
angle.
Right-angled triangles
have two sides that
are the same.
Equilateral triangles
have three sides that
are the same length.
Isosceles triangles
have three sides that
are the same length.
The lengths and angles
of triangles have the
same value.
If I tell you all the
angles that are in a
triangle you can draw
the exact triangle.
If I know one interior
angle of a triangle I
can work out all the
angles.
If I have a strip of
paper and cut it into
three pieces I can
make a triangle.
Joining two rightangled triangles along
the same length sides
makes an isosceles
triangle.
Corresponding angles
add up to 180º.
Triangles have two 90º
interior angles.