Download Geometry in the real world Part 2

Properties of a triangle
The properties of equilateral triangles:
All sides are the same length (congruent)
and all interior angles are the same size
(congruent). To find the measure of the
interior angles, we know that the sum of
all the angles is 180 degrees (from
above)... And there are three angles.
Triangle sum theoremm<A+M<c=1 80. The sum of the three
angles in any triangle sum to 180 degrees.
Third Angle theorem – The third
angles theorem states tat if two
angles of triangle e are congruent to
two angles of another triangle , then
the third angle of the triangles ar
congruent also
Exterior angle
theorem
M<4=m<2+m<3
Right triangle
A right triangle (American English)
or right-angled triangle (British
English) is a triangle in which one
angle is a right angle (that is, a 90degree angle). The relation
between the sides and angles of a
right triangle is the basis for
trigonometry.
Acute Triangle
An acute triangle is a triangle
with all three angles acute (less
than 90°). An obtuse triangle is
one with one obtuse angle
(greater than 90°) and two
acute angles. Since a triangle's
angles must sum to 180°, no
triangle can have more than
one obtuse angle.
Obtuse Triangle
An acute triangle is a
triangle with all three
angles acute (less than
90°). An obtuse triangle is
one with one obtuse angle
(greater than 90°) and two
acute angles. Since a
triangle's angles must sum
to 180°, no triangle can
have more than one obtuse
angle.
Equilateral Triangles
an equilateral triangle is a triangle
in which all three sides are equal. In
the familiar Euclidean geometry,
equilateral triangles are also
equiangular; that is, all three
internal angles are also congruent
to each other and are each 60°.
Isosceles Triangle
In geometry, an isosceles triangle is
a triangle that has two sides of equal
length. Sometimes it is specified as
having two and only two sides of
equal length, and sometimes as
having at least two sides of equal
length, the latter version thus
including the equilateral triangle as a
special case.
Scalene Triangle
A scalene triangle is a triangle that has three unequal
sides, such as those illustrated above. SEE ALSO:
Acute Triangle, Equilateral Triangle, Isosceles
Triangle, Obtuse Triangle, Triangle.