1 Geometry Section 7-1B Similar Polygons Page 468 You will need a calculator with sin/cos/tan in 2 weeks. Freshmen - TI 30 XII S recommended. Around $15. You’ll need it for Alg. II.

2 Similar Polygons: The symbol ~ means “is similar to”. ABCDE ~ MNOPQ means that two pentagons are similar and that segment AB corresponds to with segment MN, etc. The order of the letters in the similarity correspondence indicates the corresponding parts. Name all pairs of congruent corresponding angles, and write proportions using the pairs of corresponding sides. Pg. 468  A  M,  B  N,  C  O,  D  P,  E  Q Side Lengths:

3 Try It: Write the similarity correspondence between each pair of figures. Name all pairs of congruent corresponding angles and write proportions using the pairs of corresponding sides. Pg. 469  EFG ~  JIH  E  J,  F  I,  G  H EF FG GE 1 JI IH HJ 2 = = =

4 Try It: Write the similarity correspondence between each pair of figures. Name all pairs of congruent corresponding angles and write proportions using the pairs of corresponding sides. Pg. 469 QRST ~ YXWV  Q  Y,  R  X,  S  W,  T  V QR RS ST TQ 3 YX XW WV VY 1 = =

5 Try It: You can use the information for similar polygons to find unknown angle measure and side lengths in similar polygons. Pg. 470 EFGH ~ KNML Find the measures of angles E, G, and N  E = 67 o,  G = 107 o,  N = 43 o

6 Try It: You can use the information for similar polygons to find unknown angle measure and side lengths in similar polygons. Pg. 470 EFGH ~ KNML Find x, y and z x = 14, y = 15, z = 25

7 Try It: You can use the information for similar polygons to find unknown angle measure and side lengths in similar polygons. Pg. 470 EFGH ~ KNML What is the similarity ratio of KNML to EFGH? 5/2

8 Exercises: Name all pairs of congruent corresponding angles, and write proportions using the pairs of corresponding sides. #1 Pg. 471  A  E,  B  F,  C  G,  D  H Side Lengths: ABCD ~ EFGH

9 Exercises: 2-8 Pg. 471 IJKL ~ MNOP What is the similarity ratio of IJKL to MNOP? m  N = 106 o m  L = 49 o x = 9 y = 15 z = 12 2/3 What is the similarity ratio of MNOP to IJKL? 3/2

10 Exercises: Pg. 471  ABC ~  DEF. The similarity ratio of  ABC to  DEF is 7/3. If AB = 27, find DE If EF = 14, find BC Find DF/AC. 3/7

11 Exercises: #14 Pg. 471 The coordinates of Rectangle WXYZ are W(1,1), X(5,1), Y(5,4) and Z(1,4). Rectangle STUV with lower left-hand vertex S(2,7) is similar to WXYZ and its sides are parallel to the corresponding sides of WXYZ. Find the coordinates of T, U and V for the similarity ratio. ST WX = 4

12 Exercises: #15 Pg. 471 The coordinates of Rectangle WXYZ are W(1,1), X(5,1), Y(5,4) and Z(1,4). Rectangle STUV with lower left-hand vertex S(2,7) is similar to WXYZ and its sides are parallel to the corresponding sides of WXYZ. Find the coordinates of T, U and V for the similarity ratio. ST WX = 1

13 Exercises: #16 Pg. 471 The coordinates of Rectangle WXYZ are W(1,1), X(5,1), Y(5,4) and Z(1,4). Rectangle STUV with lower left-hand vertex S(2,7) is similar to WXYZ and its sides are parallel to the corresponding sides of WXYZ. Find the coordinates of T, U and V for the similarity ratio. ST WX = ½

14 Exercises: #17 Pg inch = 156 miles: If Boston and Houston are 10 ¼ in. apart on a map, what is the actual distance between the 2 cities? 1599 miles

15 Exercises: #18 Pg inch = 156 miles: If Los Angeles and New York are actually 2451 miles apart, how far apart are they on the map? inches.

16 Homework: Practice 7-1B Quiz Friday