Warm Up Monday March 24

1. What is the definition of a parallelogram?

2. What do we need to prove if we are trying to prove a parallelogram?

EOCT Week 11 #1

Similar Polygons1. Corresponding angles are congruent

2. Corresponding sides are proportional

Similarity StatementABC ~ DEF

Solve for x and y.

x = 26 cm

~ABC SLT A

B C

S

L

T

x5 cm

y = 12 cm

24 cm

10 cm 13 cm

y

222 1 2 1x x y y

A B

CD

6

x

E F

GH

18

27

x = 9

ABCD ~ EFGH. Solve for x.

Ex. A tree cast a shadow 18 feet long. At the same time a person who is 6 feet tall cast a shadow 4 feet long. How tall is the tree?

tree's shadow tree's heightperson's shadow person's height

18 x4 6

27x

The ratio of the perimeters of two similar polygons equals the ratio of any pair of corresponding sides.

A

C T

O

D G6 4 10

y

The ratio of the perimeters of CAT to DOG is 3:2 Find the value of y.

y = 4

12 cm 4 cm

Perimeter = 60 cm Perimeter = x

x = 20 cm

Find the perimeter of the smaller triangle.

Scale Factor – the ratio of a new image to its original image

• The ratio of corresponding sides

Scale Factor• When scale factor is

greater than 1, the shape gets bigger (enlargement).

• When scale factor is less than 1, but greater than 0, the shape gets smaller (reduction).

SCALE FACTOR.

2

6 2 16 3

57

3

14

6

10

10 25 1

B

D

A

C

Find the coordinates of the dilation image for the given scale factor, k.

Example 1:G(0, -2), H(1, 3), and I(4, 1); k = 2All you do is multiply k to (x, y).G’( , ), H’( , ), and I’( , )

Find the coordinates of the dilation image for the given scale factor, k.

Example 2:L(8, -8), N(0, 16), and M(4, 5); k = 1/4All you do is multiply k to (x, y).L’( , ), N’( , ), and M’( , )

k = 1/2

k = 2