Geo test

Similar Polygons

by Ryan Camacho

​What are similar polygons?

​Two polygons are considered to be similar if their corresponding angles are congruent and if the lengths are proportional.

​

​Look at the image for example.

Multiple Choice

Looking back at the same picture, what is the similarity ratio of the figure of the left compared to the right?

• 5/2

• 1/2

• 6/3

• 2

​Scale Factor

​Scale factor is the ratio of corresponding linear measurements of two similar figures.

​

​In order to answer the question above, you needed to actually find the scale factor. IXL calls it the similarity ratio.

Multiple Choice

A word was mentioned earlier... "ratio". What does the word ratio mean again?

• When the rat is on the patio. Hence ra-tio

• A ratio is a comparison between 2 ratios that are equivalent to each other

• A ratio is a comparison between two shapes

• A ratio is a comparison between 2 quantities.

​Scale Factors

​Scale factors help in constructing miniature versions of models that are super big.

​

​Think of a globe for example. The globe would be a "scaled" version of the Earth. Same with legends on a map where it shows the measures.

​How can you tell if they are to scale or similar?

​You can determine if figures are to similar if ALL of the corresponding sides are proportional.

​

​Let's take a look for example... you'll need to watch collaborate for this

Multiple Choice

To practice on proportions, is $$\frac{7}{8}=\frac{21}{24}$$  proportional?

• Yes they are proportional.

• No they are not proportional

Multiple Select

Which of the following are proportional with $$\frac{16}{40}$$  ?

• $$\frac{8}{20}$$  

• $$\frac{2}{5}$$  

• $$\frac{4}{5}$$  

• $$8$$  

Multiple Choice

Are the figures similar?

• Yes

• No

Open Ended

If two shapes have proportional corresponding sides and congruent corresponding angles, are they similar?

Multiple Select

Which of the following is proportional to $$\frac{256}{768}$$  

• $$\frac{1}{2}$$  

• $$\frac{64}{192}$$  

• $$\frac{1}{3}$$  

• $$\frac{4}{12}$$  

Multiple Choice

Are the figures similar?

• Yes they are similar

• No, they are not similar

Multiple Choice

What is the similarity ratio between segment NK and WV?

• $$\frac{17}{19}$$  

• 1

• $$\frac{40}{43}$$  

• $$\frac{1}{2}$$  

Multiple Choice

Which symbol shows that two figures are similar to each other?

• $$\approx$$  

• $$\cong$$  

• $$\sim$$  

• $$\parallel$$  

Multiple Choice

Suppose $$\frac{\left(x+4\right)}{3}=\ \frac{x}{2}$$  , what is x?

• -2

• 10

• 4

• 8

Multiple Choice

Suppose $$\frac{3}{5}=\frac{15}{25}=\frac{81}{y}$$  , What is y?

• y = 456

• y = 3

• y = 223

• y = 135

Poll

Feel like you got a better understanding of ratios, proportions, and similar figures? (5 being the highest, 1 not so much)

• 5

• 4

• 3

• 2

• 1