Answer:
poloygons with right angles
Step-by-step explanation:
Step-by-step explanation:

x varies inversely as y. This means that x is equal to the inverse of y which can be translated as x = 1/y but the problem said that x is <u>n</u><u>o</u><u>t</u><u> </u><u>e</u><u>x</u><u>a</u><u>c</u><u>t</u><u>l</u><u>y</u><u> </u><u>e</u><u>q</u><u>u</u><u>a</u><u>l</u><u> </u>to the inverse of y. Therefore, we need to introduce a factor k. Factor k will represent the word "varies" in the problem.
To illustrate:

Since we don't have the value of k, we have to solve for it by using the first values of x and y which was given as x=2 and y=20.

Now that we have the value of k, we can now solve for the value of x when y=5.

Therefore, when y is 5, the value of x is 8.
Answer:
16 rolls of ribon
Step-by-step explanation:
C = Dπ
d = r x 2
d = 100 x 2
d = 200
C = 200 x 3.14
C = 628
628 / 40 = 15.7
she should buy 16 rolls