problem 1a problem 2a problem 3a problem 4a problem 1b problem 4b problem 2b problem 3b triangles as...

PROBLEM 1A

PROBLEM 2A

PROBLEM 3A

PROBLEM 4A

PROBLEM 1B

PROBLEM 4B

PROBLEM 2B

PROBLEM 3B

TRIANGLES AS POLYGONS: CLASSIFICATION

PRESENTATION CREATED BY SIMON PEREZ RHS. All rights reserved

Standards 4 and 5

REFLEXIVE, SYMMETRIC AND TRANSITIVE PROPERTIES

EXTERIOR ANGLE THEOREM

CPCTC

ANGLE SUM THEOREM

PROBLEM 5A PROBLEM 5B

STANDARD 4:Students prove basic theorems involving congruence and similarity.

ESTÁNDAR 4: Los estudiantes prueban teoremas que involucran congruencia y semejanza.

STANDARD 5:Students prove that triangles are congruent or similar, and they are able to use the concept of corresponding parts of congruent triangles.

ESTÁNDAR 5: Los estudiantes prueban que son triángulos congruentes o semejantes y son capaces de usar el concepto de partes correspondientes de triángulos congruentes.

These are examples of POLYGONS:

These are NOT POLYGONS:

A POLYGON is a closed figure in a plane which is made up of line segments, called sides, that intersect only at their endpoints, named vertices.

Standards 4 and 5

A TRIANGLE is a three-sided polygon

Standards 4 and 5

55°

64° 61°

21°

110° 49°

RIGHT TRIANGLE

ACUTE TRIANGLE

OBTUSE TRIANGLE

CLASSIFYING TRIANGLES BY ANGLESANGLES

STANDARDS 4 and 5

PRESENTATION CREATED BY SIMON PEREZ RHS. All rights reserved

Parts of a RIGHT TRIANGLE

Leg

Leg

HYPOTENUSE

Right Angle

A

Am =180°

B

Bm+

C

Cm+If and A = 90°m then

=180°Bm+ Cm+90°- 90° -90°

=90°Bm Cm+

Conclusion: In a right triangle, both non- right angles are acute and complementary!

What kind of angles are the non-right angles in a right triangle?

CLASSIFYING TRIANGLES BY SIDESSIDES

10

4

9 22 22

9

13 13

13

SCALENE TRIANGLE

ISOSCELES TRIANGLE

EQUILATERAL TRIANGLE

Standards 4 and 5

Sample Questions

Identify the triangles by their angles and their sides

A

CB D

Right Triangles

Obtuse Triangles

Isosceles Triangles

Name the type of triangles with the following characteristics

5x 6x-5

3x+10

Find the value of x to make the triangle equilateral.

XYZ has coordinates X(2,6) Y(4,-5) Z(-3,0). Classify the triangle by angles and sides.