### Congruence Statements

When stating that two triangles are congruent, the corresponding parts must be written in the same order. For example, if we know that and are congruent then we know that:

Notice that the congruent sides also line up within the congruence statement.

We can also write this congruence statement five other ways, as long as the congruent angles match up. For example, we can also write as:

What if you were told that ? How could you determine which side in is congruent to and which angle is congruent to ?

### Examples

#### Example 1

If , what else do you know?

From this congruence statement, we know three pairs of angles and three pairs of sides are congruent. , .

#### Example 2

If , what else do you know?

From this congruence statement, we know three pairs of angles and three pairs of sides are congruent. , .

#### Example 3

Write a congruence statement for the two triangles below.

Line up the corresponding angles in the triangles:

, and .

Therefore, one possible congruence statement is

#### Example 4

If , what else do you know?

From this congruence statement, we know three pairs of angles and three pairs of sides are congruent.

#### Example 5

If , what angle is congruent to ?

Since the order of the letters in the congruence statement tells us which angles are congruent, because they are each the second of the three letters.

### Review

For questions 1-4, determine if the triangles are congruent using the definition of congruent triangles. If they are, write the congruence statement.

- Suppose the two triangles below are congruent. Write a congruence statement for these triangles.
- Explain how we know that if the two triangles are congruent, then .
- If , what else do you know?
- If , what else do you know?
- If , what else do you know?
- If , what angle is congruent to ?

### Review (Answers)

To see the Review answers, open this PDF file and look for section 4.4.