Warm Up

1. A triangle with no congruent sides is a(n)

____________________ triangle.

2. Solve for :

3. Which angle is congruent to angle 2?

4. What is the length of side in the right triangle?

5. What is the measure of angle A?

Lesson 25: SSS Triangle Congruence Geometry

Vocabulary

Corresponding sides and corresponding angles of polygons are those that are in the same position in two different polygons with the same number of sides.

Corresponding parts are indicated by the names of the polygons.

We name polygons in the order that their parts correspond.

Congruent triangles: triangles where all their corresponding sides and angles are congruent’

Triangle rigidity: a triangle can have only one size and shape

SSS and CPCTC

Postulate 13: Side-Side-Side Congruence Postulate: If three sides of one triangle are congruent to three sides of another triangle, then the triangles are congruent

CPCTC: an abbreviation for the phrase “Corresponding Parts of Congruent Triangles are Congruent”

Example

Identify the corresponding angles and sides for and

X

Y

Z L

M K

Example

Write a congruence statement for the two triangles below.

K

L

M

R P

Q

Example

Identify the congruent sides and angles of the two triangles below and write six congruence statements.

C

A

B

Z

X

Y

Example

Regina is making her own kite. It is made of two perpendicular pieces of wood, to which she will attach a plastic kite shape. The kite shape is made of two congruent triangles as shown in the picture below. Regina has already found the measures that two of the angles need to be so that the kite can fit on the wooden frame. These measure are: and . What should the measure of angle B be?

A

D B

C

Homework Questions

Correcting Homework

Get your homework out so I can stamp it.

If you do not have your homework complete, write your name on the board.

Use red pen/pencil to correct.

Trade with someone who has the homework done.

If you didn’t get it done, you need to be working on finishing it now. Remember no cheating and no work = no credit.

Make sure you write CB with your name or you will lose your citizenship points for today.

HomeworkLesson 25: a-d, 1, 2, 3, 4, 5, 7, 11, 14, 15, 21, 26