The document defines and describes different types of triangles, including: acute, obtuse, right, scalene, isosceles, equilateral, and equiangular triangles. It also covers triangle properties like congruent sides and angles, as well as the Pythagorean theorem. The document concludes with an 11 question true/false quiz to test the reader's understanding of triangles.

1. The World Of Triangles
Free powerpoints at http://www.worldofteaching.com

2. Triangles
 A triangle is a 3-
sided polygon.
Every triangle has
three sides and
three angles. When
added together, the
three angles equal
180°.

3. Acute Triangles
 A triangle in which
all three angles are
less than 90°.

4. Obtuse Triangles
 An obtuse triangle
is a triangle in
which one of the
angles is greater
than 90°.

5. Right Triangles
 A right triangle is
triangle with an
angle of 90°.

6. Scalene Triangles
 A triangle with
three unequal
sides.

7. Isosceles Triangles
 An isosceles
triangle is a triangle
with (at least) two
equal sides.

8. Isosceles Triangle Theorem
 The following
movie shows
that if two sides
of a triangle are
congruent, then
the angles
opposite those
sides are
congruent.

9. Equilateral Triangles
 An equilateral
triangle is a triangle
with all three sides
of equal length.

10. Equiangular Triangles
 An equiangular
triangle is a triangle
which has three
equal angles.

11. Congruent Triangles
 Congruent triangles
are triangles whose
corresponding
angles and sides
are congruent.
 They are exactly
the same size and
shape.

12. The Hypotenuse
 The hypotenuse of
a right triangle is
the triangle's
longest side, i.e.,
the side opposite
the right angle.

13. The Pythagorean Theorem
 For a right triangle
with legs a and b
and hypotenuse c,
a2+b2=c2.

14. Triangle Quiz
 Please complete the following quiz
that covers the information that was
just presented to you.

15. Question 1
 If a triangle has  Answer:
three unequal sides  A) Scalene
it is a ______
triangle.
 A) Scalene
 B) Obtuse
 C) Isosceles

16. Question 2
 A triangle which  Answer:
has three equal  C) Equiangular
angles is a ______
triangle.
 A) Acute
 B) Equilateral
 C) Equiangular

17. Question 3
 A triangle with (at  Answer:
least) two equal  B) Isosceles
sides is a ______
triangle.
 A) Scalene
 B) Isosceles
 C) Congruent

18. Question 4
 Two triangles that  Answer:
are equal are  C) Congruent
called ______
triangles
 A) Acute
 B) Obtuse
 C) Congruent

19. Question 5
 A triangle with all  Answer:
three sides of equal  A) Equilateral
length is a ______
triangle.
 A) Equilateral
 B) Right
 C) Equiangular

20. Question 6
 A triangle with an  Answer:
angle of 90° is a  B) Right
______ triangle.
 A) Acute
 B) Right
 C) Congruent

21. Question 7
 A triangle in which  Answer:
all three angles are  B) Acute
less than 90° is a
______ triangle.
 A) Right
 B) Acute
 C) Scalene

22. Question 8
 A triangle in which  Answer:
one of the angles is  A) Obtuse
greater than 90° is
a ______ triangle.
 A) Obtuse
 B) Isosceles
 C) Acute

23. Question 9
 What is the  Answer:
Hypotenuse of a  B) The side
right triangle? opposite the right
 A) The smallest angle.
angle.
 B) The side
opposite the right
angle.
 C) The right angle.

24. Question 10
 The Pythagorean  Answer:
Theorem states …  C) a2+b2=c2
 A) πr2
 B) (a+b)2/2=c
 C) a2+b2=c2

25. Question 11
 Use the  Answer:
Pythagorean  c = 13
Theorem to solve
the following:
 a= 5
 b = 12
 c=?