Presentation on theme: "EXAMPLE 2 Find the scale factor"— Presentation transcript:
1 EXAMPLE 2Find the scale factorDetermine whether the polygons are similar. If they are, write a similarity statement and find the scale factor of ZYXW to FGHJ.
2 EXAMPLE 2Find the scale factorSOLUTIONSTEP 1Identify pairs of congruent angles. From the diagram, you can see that Z F, Y G, and X H. Angles W and J are right angles, so W J. So, the corresponding angles are congruent.
3 EXAMPLE 2Find the scale factorSOLUTIONSTEP 2Show that corresponding side lengths are proportional.ZYFG2520=54=YXGH3024=54=XWHJ1512==54WZJF2016==54
4 EXAMPLE 2Find the scale factorSOLUTIONThe ratios are equal, so the corresponding side lengths are proportional.So ZYXW ~ FGHJ. The scale factor of ZYXW toFGHJ isANSWER54.
5 EXAMPLE 3Use similar polygonsIn the diagram, ∆DEF ~ ∆MNP. Find the value of x.ALGEBRA
6 EXAMPLE 3 Use similar polygons SOLUTION The triangles are similar, so the corresponding side lengths are proportional.MNDENPEF=Write proportion.=12920xSubstitute.12x = 180Cross Products Propertyx = 15Solve for x.
7 GUIDED PRACTICEfor Examples 2 and 3In the diagram, ABCD ~ QRST.2. What is the scale factor of QRST to ABCD ?12ANSWERFind the value of x.ANSWER8