1. Holt CA Course 1 8-6 Congruent Polygons MG3.4 Demonstrate an understanding of conditions that indicate two geometrical figures are congruent and what congruence means about the relationship between the sides and angles of the two figures. California Standards

2. Holt CA Course 1 8-6 Congruent Polygons A correspondence is a way of matching up two sets of objects. Congruent figures have the same shape and size. If two polygons are congruent, all of their corresponding sides and angles are congruent. To write a congruence statement, the vertices in the second polygon have to be written in order of correspondence with the first polygon.

3. Holt CA Course 1 8-6 Congruent Polygons Additional Example 1: Writing Congruent Statements A corresponds to Q. A  Q B corresponds to R. B  R C corresponds to P. C  P The congruence statement is triangle ABC  triangle QRP. A. Write a congruence statement for each pair of polygons. 55

4. Holt CA Course 1 8-6 Congruent Polygons Additional Example 1: Writing Congruent Statements The vertices in the first pentagon are written in order around the pentagon starting at any vertex. D corresponds to M. D  M E corresponds to N. E  N F corresponds to O. F  O The congruence statement is pentagon DEFGH  pentagon MNOPQ. G corresponds to P. G  P H corresponds to Q. H  Q B. Write a congruence statement for each pair of polygons.

5. Holt CA Course 1 8-6 Congruent Polygons Check It Out! Example 1 A corresponds to S. A  S B corresponds to T. B  T C corresponds to Q.C  Q The congruence statement is trapezoid ABCD  trapezoid STQR. A B C D Q R ST D corresponds to R. D  R | || ||| |||| | || ||| |||| A. Write a congruence statement for each pair of polygons. 60° 120° 60° 120°

6. Holt CA Course 1 8-6 Congruent Polygons Check It Out! Example 1 A corresponds to M. A  M B corresponds to N. B  N C corresponds to O. C  O The congruence statement is hexagon ABCDEF  hexagon MNOPQL. D corresponds to P. D  P E corresponds to Q. E  Q A B C D E F N O P Q L M F corresponds to L. F  L B. Write a congruence statement for each pair of polygons. 140° 110° 140° 110°

7. Holt CA Course 1 8-6 Congruent Polygons Additional Example 2: Using Congruence Relationships to Find Unknown Values In the figure, quadrilateral VWXY  quadrilateral JKLM. a = 16 –8 –8 Subtract 8 from both sides. A. Find a. a + 8 = 24 WX  KL

8. Holt CA Course 1 8-6 Congruent Polygons In the figure, quadrilateral VWXY  quadrilateral JKLM. 6 6 6b = 30 Divide both sides by 6. B. Find b. 6b = 30 ML  YX b = 5 Additional Example 2: Using Congruence Relationships to Find Unknown Values

9. Holt CA Course 1 8-6 Congruent Polygons 5c = 85 J  V 5 5 5c = 85 Divide both sides by 5. C. Find c. c = 17 In the figure, quadrilateral VWXY  quadrilateral JKLM. Additional Example 2: Using Congruence Relationships to Find Unknown Values

10. Holt CA Course 1 8-6 Congruent Polygons Check It Out! Example 2 In the figure, quadrilateral JIHK  quadrilateral QRST. A. Find a. 3a3a 4b° 6 30° Q 120° R S H I J K 3a = 6 3 3 a = 2 c + 10° T 3a = 6 IH  RS Divide both sides by 3.

11. Holt CA Course 1 8-6 Congruent Polygons B. Find b. Divide both sides by 4. 4 4 4b = 120 b = 30 4b = 120 H  S Check It Out! Example 2 In the figure, quadrilateral JIHK  quadrilateral QRST. 3a3a 4b° 6 30° Q 120° R S H I J K c + 10° T

12. Holt CA Course 1 8-6 Congruent Polygons C. Find c. c = 20 Subtract 10 from both sides. –10 c + 10 = 30 K  T Check It Out! Example 2 3a3a 4b° 6 30° 90° Q 120° 90° R S H I J K T c + 10° In the figure, quadrilateral JIHK  quadrilateral QRST.