Lesson 2 1 Congruent Figures Name corresponding angles

Lesson 2. 1 Congruent Figures Name corresponding angles and corresponding sides of congruent figures; identify congruent figures (CC. SS. 8. G. 2)

Warm-Up 1. Given 3 x + y = 3, if y = 3 find the value of x 2. 4 x + 2 x – 2 = 42 solve for x 3. Find the volume of a cylinder if the diameter is 4 inches.

Transformation – a change in the ______, _____ shape , or size _____ position of a figure. Rigid Transformation – a change in the position of a figure that does not change its ________ or ________. size shape original Pre-image – the _____ figure in a transformation. resulting figure (new) in a transformation. Image – the _______ Isometry – a transformation in which the original figure and its image are congruent ______. Prime – a notation to identify new images being created. It looks like this: A’ or A’’’’

Transformations on the Coordinate Plane Line of reflection NOT A RIGID TRANSFOMRATION NOT AN ISOMETRY

Transformations Notation •

How can you identify congruent triangles? Two figures are congruent when they have the same size and the same shape.

Congruent shapes

Transformation • Translation (slide), Reflection (mirror), Rotation (turn) maintain the congruency of the shapes. • Dilation (enlarge/reduce) does not maintain the congruency of the shapes.

Congruent: YES? No?

Yes or no?

Yes or no?

Yes or no?

Yes or no?

More Flips

Identifying Congruent Figures Two figures are congruent when corresponding angles and corresponding sides are congruent. Triangle ABC is congruent to Triangle DEF.

Problem 2: The figures are congruent. Name the corresponding angles and the corresponding sides.

Problem 3

Problem 4