Question

The polygons below are similar. Find the value of y.



4.5

7.5

12

16

Answer 1

@phi do you know how to do this ?

Answer 2

@amistre64

Answer 3

@happyfeet8040

Answer 4

can you match up which side in the little shape goes with which side in the big shape?

Answer 5

uhm yes, a=d , b=e, and c=f ? is that right ?

Answer 6

I don't understand what you mean. there are no sides labeled a or d, for example.

Answer 7

oh sorry i was doing angles. so it would be x and 12, 10 and z, 8 ad 6, and y and 6 . is that right ?

Answer 8

so just those ones? and how do you find the value of y? sorry im really bad at math..

Answer 9

thank you .

Answer 10

similarity is an idea.
write down a ratio of one side of the little shape divided by the *corresponding* side of the big shape.
say you pick the side y of the little shape. what is the corresponding side of the big shape?

Answer 11

the corresponding side would be 6

Answer 12

would it be 4.5?

Answer 13

and how do you write the ratio? just
\[ \frac{y}{6} \]
little over big
now write another ratio of little over big. the idea is to pick the sides where we know *both* sides as numbers.

Answer 14

i think i got this question! thanks so much, i have 1 more, its similar to this could you help ? (: if you arnt too busy(:

Answer 15

The two triangles below are similar. What is the similarity ratio of ΔABC to ΔDEF?



2:1

1:2

2:5

5:2

Answer 16

you should have done
\[ \frac{y}{6}= \frac{6}{8} \]
I always simplify first, if I can 6/8 is ¾
\[ \frac{y}{6}= \frac{3}{4} \]
multiply both sides by 6
\[ \frac{y}{6}\cdot 6= \frac{3}{4}\cdot 6\\
y= \frac{3}{2}\cdot 3= \frac{9}{2}= 4.5
\]

Answer 17

thats what i got! thank you so much it actually makes a little sense now

Answer 18

For your next question, you have to find *corresponding* sides (where you know the length of both sides)

Answer 19

for the next question i THINK its 2:5

because of the corresponding sides. is that correct?(:

Answer 20

then (they want ABC: DEF) so writ the ABC number first.

This one is a trick question. We can't trust the picture. We assume they wrote ABC and DEF in that order because A goes with D, B with E and C with F

Answer 21

so actually it would be 5:2 because those are the sides that correspond?

Answer 22

the only side labeled in DEF is side DF
because they wrote ABC=DEF D->A and F->C, so side AC is the corresponding side in the other triangle

Answer 23

wait, it would actuaslly be 2:1 , correct? because 4:2 are corresponding sides and if you simplify that, its 2:1 ?

Answer 24

yes

Answer 25

yay! thank you soooo much!!!

Answer 26

yw