Question

Find the length of: AC and AD.

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Answer 1

Avoid hyperlinking to facebook-hosted images... the URL includes information which can lead to your profile ID and personal information.

Answer 2

@oldrin.bataku okay, i will next time xD

Answer 3

@perurabo don't i need to know the adjacent side? or even opposite? Dx

Answer 4

really? you can use 90 degrees? O_O

Answer 5

inverse... as in cotangent?

Answer 6

Numerical lengths can't be ascertained.

However, it is certain that AD = 2DC

Answer 7

@qweqwe123123123123111 sorry, but how are you certain that AD = 2DC? DX can you explain to me ;_; and there should be a way to find it because my teacher is a type of teacher who is like that... gives really hard problems and no one really knows how and then after enjoying seeing everyone's clueless faces, he shows us how to do it on the board. T____T

Answer 8

The reason AD = 2DC is because the all the sides scale similarly.
Triangle DEC is similar to triangle ABC.
Since DE is 3 and AB is 9, that means that BC is 3 times as long as EC, which means that BE is 2EC.
It also means that AC is 3 times as long as DC, which is why AD = 2DC.
The reason you can't assign specific numerical lengths to these sides is because there's no way of telling how far apart they are.

Answer 9

Okay, thanks. I understand that part now but I feel like putting, "Not enough information" isn't right. Cause, my teacher is a really smart guy. Not sure if this will give you an idea of his intelligence, but he once worked for NASA. He didn't have a small role in projects as well. Most of his students believe that he never does supply enough information for his problems but again, he always manages to prove us wrong. Unless, you are right, and he is trying to pull a trick on us, which he usually does. For example, he said he would give us 250+ problems for our summer homework. Turns out he trolled us and gave us 110 instead. :'DDD

Answer 10

you can have all possible values for AC greater than 9, fixing AB and DE values at 9 and 3

Answer 11

okay, thanks. I don't think we can have a definite answer than. xD I'm going to ask my other math teacher for help as well and if I ever find out, I'll post it up here. < If anyone is curious.

Answer 12

there is a definite answer that AC can take all values greater than 9

Answer 13

thats what your teacher wants you to see

Answer 14

really? so its sorta like the domain of a function? as long as it works when we put it in?

Answer 15

Interesting way of looking at it, but yes, it's VERY similar to a function.

You could say that AC is f(x) where x=3DC

Answer 16

Uhh, conversations about NASA, evil genius teachers, and fake functions aside,
this problem does have a specific answer.

Using the similarities of triangles, and good old Pythagorean Triples, We have a right triangle with the following sides :

( 9, 12, 15 )

Answer 17

While a nice, neat 3-4-5 triangle is admittedly far more likely than not to be what someone is looking for, there is nothing in the problem which prohibits the triangle from being (9-21-22.847) or any other right triangle with a side of 9. Even if one demands integer sides, there's still nothing to prohibit the triangle from being 9-40-41.

Regardless of how likely it may be, (9, 12, 15) is merely *A* solution; it is not *THE* solution.

Answer 18

exactly !