30. A plastic cover is made for the pool. The cover will rest on the top of the pool and will include a
wedge-shaped flap that forms a 45° angle at the center
of the cover, as shown in the figure below. A zipper
will go along 1 side of the wedge-shaped flap and
around the arc. Which of the following is closest to the
length, in feet, of the zipper?

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

60 for the first and 130 for the second

step-by-step explanation:

the answer is:

the correct option is the option b.

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!

320ft

step-by-step explanation:

120 divided by 3 equals 40

40 times 4=160

160 times 2=320