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Similar Polygons - Nexuslearning.net

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xy xy<br />

Using<br />

Algebra<br />

GUIDED PRACTICE<br />

Vocabulary Check ✓<br />

Concept Check ✓<br />

Skill Check ✓<br />

THEOREM<br />

THEOREM 8.1<br />

If two polygons are similar, then the ratio<br />

of their perimeters is equal to the ratios of<br />

their corresponding side lengths.<br />

If KLMN ~ PQRS, then<br />

KL<br />

= = <br />

PQ<br />

LM<br />

= <br />

QR<br />

MN<br />

= <br />

RS<br />

N<br />

N<br />

KL + LM + MN + NK<br />

<br />

K<br />

PQ + QR + RS + SP<br />

.<br />

SP<br />

EXAMPLE 5<br />

Using <strong>Similar</strong> <strong>Polygons</strong><br />

Quadrilateral JKLM is similar to<br />

quadrilateral PQRS.<br />

Find the value of z.<br />

SOLUTION<br />

Set up a proportion that contains PQ.<br />

KL JK<br />

= QR<br />

PQ<br />

Write proportion.<br />

15<br />

= <br />

6<br />

10<br />

<br />

z<br />

Substitute.<br />

z = 4 Cross multiply and divide by 15.<br />

1. If two polygons are similar, must they also be congruent? Explain.<br />

Decide whether the figures are similar. Explain your reasoning.<br />

2. 3.<br />

15<br />

In the diagram, TUVW ~ ABCD.<br />

4. List all pairs of congruent angles and write the<br />

statement of proportionality for the polygons.<br />

5. Find the scale factor of<br />

TUVW to ABCD.<br />

6. Find the length of TW Æ .<br />

7. Find the measure of TUV.<br />

8<br />

3<br />

10<br />

W<br />

K<br />

J 10<br />

M<br />

L<br />

K<br />

6<br />

89<br />

5<br />

82<br />

7<br />

87<br />

4<br />

M<br />

T 15 U<br />

23<br />

15<br />

10<br />

D<br />

6<br />

V<br />

S<br />

L<br />

89<br />

82<br />

A<br />

P<br />

12<br />

14<br />

102<br />

8.3 <strong>Similar</strong> <strong>Polygons</strong> 475<br />

q<br />

q<br />

6<br />

z<br />

R<br />

P<br />

R S<br />

9 B<br />

70<br />

C<br />

8

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