Date:Topic: Congruent Figures (6.6) Warm-up

Construct a segment congruent to

Construct an angle congruent to

When congruent segments and congruent angles are combined to make a shape, those shapes are called congruent figures.Congruent figures have all congruent sides and angles.

Example:

If all of the corresponding sides and all of the corresponding angles of a shape are congruent, then the shapes are congruent.Therefore,

CA FD

For two triangles to be congruent, all corresponding side lengths and all corresponding angle measures must be congruent.

Corresponding means the same location of each side length or angle on each triangle.

Example: Given

A I

AB IH

always use the same order when naming corresponding parts

Therefore, ≅ ≅ ≅ ≅ ≅ ≅ ≅ ≅

Congruence works for other shapes as well. As long as all corresponding angles and corresponding sides are congruent, then the shapes are congruent.Example: JKLM≅QPON

You can use congruence to find missing side lengths or angle measures.

Example: Given , find the missing side lengths and angle measures.

≅

Use this same method to find the other missing values: = 11 cm = 28 cm = 30 cm = 78° = 36°

11 cm

30 cm 28 cm

36°

66°

m J 6666

11 cm

28 cm30 cm

36

78

78°