ABC ~ XYZ

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GEOMETRY HELP ABC ~ XYZ Two polygons are similar if (1) corresponding angles are congruent and (2) corresponding sides are proportional. Complete each statement. a. mB = ? b. BC YZ = ? XZ a. B Y and mY = 78, so mB = 78 because congruent angles have the same measure. b. Because AC corresponds to XZ, . = BC YZ AC XZ Quick Check Similar Polygons LESSON 7-2 Additional Examples

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BC YZ. ? XZ. =. a.  B  Y and m  Y = 78, so m  B = 78 because congruent angles have the same measure. AC XZ. BC YZ. b. Because AC corresponds to XZ ,. =. Similar Polygons. LESSON 7-2. Additional Examples. ABC ~ XYZ. Complete each statement. a. m  B = ? b. - PowerPoint PPT Presentation

Transcript of ABC ~ XYZ

Page 1: ABC  ~     XYZ

GEOMETRYHELP

ABC ~ XYZ

Two polygons are similar if (1) corresponding angles are congruent and (2) corresponding sides are proportional.

Complete each statement. a. mB = ?

b. BCYZ

= ? XZ

a. B Y and mY = 78, so mB = 78 because congruent angles have the same measure.

b. Because AC corresponds to XZ, .=BCYZ

ACXZ

Quick Check

Similar PolygonsLESSON 7-2

Additional Examples

Page 2: ABC  ~     XYZ

GEOMETRYHELP

Determine whether the parallelograms are similar. Explain.

Corresponding sides of the two parallelograms are proportional.

Although corresponding sides are proportional, the parallelograms are not similar because the corresponding angles are not congruent.

Check that corresponding angles are congruent.

B corresponds to K, but mB ≠ mK, so corresponding angles are not congruent.

Check that the corresponding sides are proportional.

= = = =ABJK

24

BCKL

12

CDLM

24

DAMJ

12

Similar PolygonsLESSON 7-2

Additional Examples

Quick Check

Page 3: ABC  ~     XYZ

GEOMETRYHELP

If ABC ~ YXZ, find the value of x.

Because ABC ~ YXZ, you can write and solve a proportion.

x = 401230

Solve for x.

x = 16

= Corresponding sides are proportional.ACYZ

BCXZ

= Substitute. x 40

1230

Similar PolygonsLESSON 7-2

Additional Examples

Quick Check

Page 4: ABC  ~     XYZ

GEOMETRYHELP

A painting is 24 in. wide by 36 in. long. The length of a

postcard reduction of the painting is 6 in. How wide is the postcard?

The postcard and the painting are similar rectangles, so you can write a proportion. Let x represent the width of the postcard.

x = 4

The postcard is 4 in. wide.

Similar PolygonsLESSON 7-2

Additional Examples

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postcard width postcard lengthpainting width painting length= Corresponding sides are proportional.

= Substitute. x 24

6 36

6 36x = 24 Solve for x.

Page 5: ABC  ~     XYZ

GEOMETRYHELP

The dimensions of a rectangular tabletop are in the golden

ratio. The shorter side is 40 in. Find the longer side.

Let represent the longer side of the tabletop.

= 64.72 Cross-Product Property

The table is about 65 in. long.

Similar PolygonsLESSON 7-2

Additional Examples

Quick Check

40

= Write a proportion using the golden ratio. 1.618 1