SOLUTION: A picture has a ratio of length to width of 8 to 5. If the width is 35 cm, calculate the length of the picture. I know how to do proportions but I have no idea when it comes to

Algebra ->  Proportions -> SOLUTION: A picture has a ratio of length to width of 8 to 5. If the width is 35 cm, calculate the length of the picture. I know how to do proportions but I have no idea when it comes to       Log On


   

Question 12142: A picture has a ratio of length to width of 8 to 5. If the width is 35 cm, calculate the length of the picture.
I know how to do proportions but I have no idea when it comes to propotions with word problems.
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = length
35 cm = width

Ratios are really easy, and as long as you are consistent, you can hardly miss them. Set up a ratio of one variable to another, always using the same variable for the numerator and the same one for the denominator:
%28Length%29%2F%28Width%29+=+8%2F5=+x%2F35

Remember, a%2Fb=c%2Fd means that ad=bc

In the same way:
8%2F5+=+x%2F35 means that 8%2A35+=+5%2Ax

Divide both sides by 5:
%288%2A35%29%2F5+=+%285%2Ax%29%2F5
8%2A7+=+56+=+x

R^2 at SCC