CONGRUENCE

MATH 8

REVIEW VOCABULARY

Angle:

The space formed between where

two rays cross at a vertex

Measured in degrees º

- can be acute, right, obtuse

REVIEW VOCABULARY

Side:

The line segment created when rays

from two different angles are joined

Measured in a variety of units

REVIEW VOCABULARY

Polygon:

A closed shape made up of straight line segments

that form sides and angles

These are NOT Polygons

NAMING PARTS OF A POLYGON

Entire Shape:

Sides:

Angles:

Begin at any vertex and then list the others by traveling CW or CCW around the shape, but not going across the middle of the shape

List the two vertices at the end of the line segment,

place a bar over them

order of the vertices will become important

stands for measure of side BC, and gives the length with appropriate units

use the angle symbol

vertex only

list 3 points that form the angle, vertex in middle

ANSWER THE QUESTIONS BELOW

Which angle has a measure of 96º?

Name it 3 different ways

Which side has a length of 11cm?

Which of these is NOT a correct way to

name the entire shape?

BCDA DCBA BADC DACB CDAB

VOCABULARY

Congruent Polygons:

- Polygons equal in shape and measure.

If one polygon can become another with a series

of only rigid transformations then the two polygons

are congruent

- congruent angles are shown with the same number of arc marks,

congruent sides are shown with the same number of tic marks

Congruent Corresponding Parts:

- corresponding (matching) parts of polygons are marked to show congruence

- all corresponding measures must be equal

(sides are exactly the same length,

angles are exactly the same degrees)

Determine whether each pair of polygons is congruent. Explain why it is or is not.

For the polygons above, what specific transformation(s) could take the shape on the left to become the one on the right?

Corresponding sides have the same number

of tic marks

Corresponding angles have the same number

of arc marks, AND

Congruent

Not Congruent

Corresponding sides have the same number

of tic marks

BUT, No congruent angles

Reflection over a vertical line

Possibly a translation depends on vertical line placement

No rigid transformation will make one shape become the other

Congruence Statements:

- symbol for congruent is

Statements about equal parts in two congruent polygons,

both angle measures and side lengths

Write congruence statements for the set of congruent figures.

Identify all pairs of congruent corresponding parts.

For the polygons above, what specific transformation(s) could take the shape on the left to become the one on the right?

Look for matching

arc and tic marks

Angles

Sides

Matching sides need to match

the order of the vertices!

Reflection over a vertical line (and a translation if necessary)

For the polygons above, what specific transformation(s) could take the shape on the left to become the one on the right?

Angles

Sides

Reflection across the y-axis, and a translation down 2 units

Triangle ABC is congruent to triangle XYZ. Write congruence statements for the set of congruent figures. Identify all pairs of congruent corresponding parts.

For the polygons above, what specific transformation(s) could take the shape on the left to become the one on the right?

Look at the order of the letters!

Rotation 90° CCW around point C, and a translation right and up a little

Look at the order of the letters!

Draw arc and tic marks on the figure to identify the corresponding parts.

Find the value of x