Similarity

​Similarity

Some text here about the topic of discussion

​Some text here about the topic of discussion.

Take a look at these 2 triangles

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Open Ended

Which side corresponds to side CB?

SCALE FACTOR

Scale factor: The amount each side of a figure is multiplied by when the figure is proportionally enlarged or reduced in size.

Some text here about the topic of discussion

Open Ended

What is the scale factor from the small "C" to the big "C"?

Proportion

An equation of two equivalent fractions

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You can solve them by cross multiplying. ​

Some text here about the topic of discussion

Multiple Choice

Which equation would be the correct proportion to set up?

• $$\frac{8}{x}=\frac{72}{6}$$  

• $$\frac{x}{6}=\frac{72}{8}$$  

• $$\frac{x}{8}=\frac{72}{6}$$  

• $$\frac{6}{72}=\frac{x}{8}$$  

Open Ended

Solve the proportion for this problem. Use cross multiplication. Write your answer as x=#

​Some text here about the topic of discussion.

Rochida drew ΔABC below and then dilated through point A to create ΔAB′C′.

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These two triangles are difficult to compare, so Rochida redrew them separately.​

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Draw

Write a proportion (fraction = fraction)

Similarity Conditions

​Angle Angle

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Side-Angle-Side​

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Side-Side-Side​

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If you have 2 angles that are the same, triangles are similar.

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If you have 2 sides that are proportional and the angle between them is congruent, triangles are similar.​

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If you have 3 sides that are proportional, triangles are similar.​

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Some text here about the topic of discussion

Multiple Choice

What is the similarity statement for the triangle pair?

• ΔXYZ is similar to ΔNEW

• ΔXZY is similar to ΔNWE

• ΔZYX is similar to ΔENW

• ΔYZX is similar to ΔNWE

Multiple Choice

Is Triangle ABC similar to Triangle DEF?

• Yes, by SSS

• Yes, by SAS

• No, because the corresponding sides are not proportional.

• No, because we don't know if the included angles are congruent.

Multiple Choice

Determine if Triangle VEZ is similar to Triangle MAG

• No, because all of the angles are congruent.

• Yes, by AA

• No, because the sides are not proportional.

• Yes, by SAS

Multiple Choice

State if the triangles in each pair are similar. If so, state how you know they are similar.

• Yes, AA Similarity

• Yes, SSS Similarity

• Yes, SAS Similarity

• Not Similar

Multiple Choice

State if the triangles in each pair are similar. If so, state how you know they are similar.

• Yes, AA Similarity

• Yes, SSS Similarity

• Yes, SAS Similarity

• Not Similar