What is a ratio?
this unit in math i've been learning about ratios and the word has been thrown around a lot, but i still don't understand what a ratio is.

A ratio is a numerical comparison between 2 similar objects, persons, figures, or ideas.  For example if I have 5 cards and you have 10, I can say that you have twice as many cards as I do.  Or take my 5 cards and multiply by 2 to get your 10.  Another way I can say it is that the ratio between your cards to my cards is 2 to 1 or 2:1 (both mean the same thing).  Let's say now I have x cards, but knowing that I have a 2:1 ratio from your cards to mine, I can say that you have 2x cards.  There is alot more I can say, but this should get you started.  Feel free to ask any following questions.

The answer is below

Step-by-step explanation:

AD = X + 8 ∠D = 2y +13 ∠C = 16 - x CB = 5y+4

In a parallelogram, consecutive angles are supplementary and opposite sides are equal.

Therefore for parallelogram ABCD, AB = CD, CB = AD

Since AD = CB (opposite sides of a parallelogram are equal):

x + 8 = 5y + 4

5y - x = 8 - 4

5y - x = 4             (1)

∠C + ∠D= 180° (consecutive angles of a parallelogram are supplementary). Therefore:

16 - x + 2y + 13 = 180

2y - x + 29 = 180

2y - x = 180 -29

2y - x = 151             (2)

To find x and y, subtract equation 1 from equation 2:

3y = -147

y = -49

Put y = -49 in equation 2

2(-49) - x = 151

x = -98 - 151

x = -249