Question

Please Help! Define the variables.Then write a direct variation to model each relationship. The perimeter of a regular octagon varies directly with the length of one side of the octagon.

Answer 1

why don't you pick some letters for your variable names?

Answer 2

its up to you. I dont even know how many variables i would need nonetheless how to set up the equation. :(

Answer 3

This is the key statment

The perimeter of a regular octagon varies directly with the length of one side of the octagon.

math is like texting, you leave out all the extra stuff.

Answer 4

So an octagon has 8 sides so the perimeter would be all of those sides added up,but we need to find what the length of one side equals. How would i set this up as an equation?

Answer 5

it would help to know that direct variation means
y=kx where y and x are variables and k is some constant.

Look at
The *perimeter* of a regular octagon *varies directly* with the *length of one side* of the octagon.

you could say
perimeter = k * "length of one side"

math people would shorten up the words to one letter, and find a number for k

Answer 6

btw, the 8 sides of the octagon are assumed to be the same length

Answer 7

Ok so then would it be K(8)=y?

Answer 8

no

perimeter = k * "length of one side"

math people would shorten up the words to one letter, and find a number for k

Answer 9

so then what would it be,for the equation.

Answer 10

do you have an idea what the variables are?

Answer 11

yeah,they are letters that represent something unknown in an equation. You usually find out what they are by evaluating the equation.

Answer 12

what are the variables for this problem?

you said
"the perimeter would be all of those sides added up"

Answer 13

Okay so your trying to write a direct variation of the relationship between the perimeter of an octagon and the length of one side.Since each side is the same if u took the perimeter then divided it by 8 then you would get the length of one side.

Answer 14

yes, that sounds good. That would be exactly what you would do if you wanted to say
the side varies directly with the perimeter.

They want you to do it the other way round: given the length of 1 side, what is the perimeter?

Answer 15

The length of the side is multiplied by 8. Or u could add that number together 8 times.

Answer 16

yes, exactly right

now how do you say that using letters? (and use multiplying because direct variation uses multiplying)

Answer 17

Hmm...would it be x= one side and y= the total perimeter. So then it would be whatever the side is.. which we dont know times 8. So 8x=y?

Answer 18

gack! you are thinking like a math person!

Answer 19

is that good?

Answer 20

yes, thinking is a good habit. Just don't be a "know it all"

Answer 21

oh okay and no way. I dont think its possible for me to be a know it all anyway.

Answer 22

Do u think you could help me with another question?