You need to determine how much paper you need to cover the lateral side of the cylinder shown in the picture. For this, you have to calculate the surface area of the cylinder, which you can do using the following formula:

Where
A is the area
π is the number pi, for the calculations we usually use up to the first two decimal values of this number, 3.14
r is the radius
h is the height of the cylinder
The given cylinder has a height of h=15m and a diameter of d=6m
To calculate the lateral area you need to use the radius. The diameter is twice the radius, so to determine the radius of the cylinder you have to divide the diameter by 2

Now you can calculate the lateral area as follows:

Charlie will need 282.6 m² to cover the lateral side of the cylinder.
If the ratio is 14 childen to every 5 teachers, and there are thirty teachers... there are 84 children. hope I could help!
Simply the answer would be .38 if this is not correct then i failed
Given:
Total number of marbles in the bag = 150
There are 21 blue marbles for every 4 white marbles.
To find:
The number of blue marbles in the bag.
Solution:
Since, there are 21 blue marbles for every 4 white marbles, therefore the ratio of blue marble to white marbles is 21:4.
Let the number of blue marbles be 21x and white marbles be 4x.
Total number of marbles in the bag = 150


Divide both sides by 25.


Now,



Therefore, the number of blue marbles is 126.