Question

will medal + fan!! please help!!!
Bradley and Kelly are out flying kites at a park one afternoon. A model of Bradley and Kelly's kites are shown below on the coordinate plane as kites BRAD and KELY, respectively:

Answer 1

Which statement is correct about the two kites?

A. They are not similar because segment BR to segment KE is 1:2 and segment KY to segment BD is 2:1.

B. They are similar because segment BR to segment KY is 1:2 and segment BD to segment YL is 1:2.

C. They are not similar because segment YL to segment DA is 1:2 and segment KY to segment BD is 2:1.

D. They are similar because segment KY to segment BD is 2:1 and segment YL to segment DA is 2:1.

Answer 2

@dan815

Answer 3

@perl

Answer 4

@TuringTest pls help me out D:

Answer 5

@texaschic101

Answer 6

let's try out the different possibilities:
"They are not similar because segment BR to segment KE is 1:2 and segment KY to segment BD is 2:1."
Let's look at those segments
http://prntscr.com/6sg0fi
If these two pairs of segments are similar, is that enough to show the kites are similar?

Answer 7

yes i think

Answer 8

think about how the other half of the figure could be different if we don't check it
http://prntscr.com/6sg2tm
are these two figures similar?

Answer 9

no, i dont think so

Answer 10

correct, so this means that showing BR to segment KE (the red sides) are 1:2 and segment KY to segment BD (the blue sides) are 2:1 is not enough to prove similarity of the whole shape

Answer 11

ohhhh

Answer 12

yep, so we can check the next possible answer...

Answer 13

They are similar because segment BR to segment KY is 1:2 and segment BD to segment YL is 1:2.

Well let's mark those segments like we did last time, with BR and KY in red, and BD and YL in blue

Answer 14

okay. i can do that in my head

Answer 15

ok, if those sides are similar, is that enough to prove the whole shape is similar?

Answer 16

sorry i was gone for a while i had to do something

Answer 17

that's ok

Answer 18

hmm no

Answer 19

i dont think the 2nd one is right either

Answer 20

correct, the 2nd one is no better than the first, it's just flipped

Answer 21

how about the third?

Answer 22

i think that ones wrong too

Answer 23

why?

Answer 24

well it only includes 2 segments and i thought you have to include more to find out if its similar

Answer 25

idk if that makes sense

Answer 26

Yes it makes sense, but think about another example like a square
if you have two rectangles, all you need to determine if they are similar is two sides. If two of the sides are similar, and a third is not, both the shapes can't possibly be rectangles. If that makes any sense.

Answer 27

so in this example we are looking at these sides
http://prntscr.com/6sganu

Answer 28

yeah that makes sense

Answer 29

see, if I alter the other sides, it's not a kite anymore:
http://prntscr.com/6sgck7

Answer 30

right right..

Answer 31

so now we have to check if the statement is even true
"segment YL to segment DA is 1:2"
is that true?

Answer 32

im not sure. how do you exactly find out the ratio part??

Answer 33

well if YL:DA is 1:2, which segment should be longer?

Answer 34

I am trying to help you find the answer in fewer steps than it would take to calculate everything. Think about things to check that require the least work.

Answer 35

okay. thank you for that by the way

Answer 36

and segment YL is the longer one

Answer 37

right, so is YL:DA in ratio 1:2

Answer 38

no, it should be 2:1 right? because YL is longer

Answer 39

correct, so this answer makes no sense since it's not true

Answer 40

so by process of elimination we should have our answer, although it is best to check

Answer 41

how do you check it?

Answer 42

in order of least to most work:
check that the statement would imply similarity
check that the statement is true from a glance
calculate the lengths of the sides to verify that the statement is true

(I actually have a slightly different way to do the last step)

Answer 43

the first two answers were wrong because they would not have implied similarity
the third answer was wrong because you could tell it wasn't true by just looking at the figure

Answer 44

okay that makes sense!!!

Answer 45

tysm you helped me so much

Answer 46

you are welcome!